The episode opens in Baltimore, MD, where a strange figure with glowing eyes is watching a businessman from under a sewer grating. The businessman travels back to his office late in the evening, and makes a phone call to his wife. He doesn't notice the screws on the air vent in his office unscrewing from the inside, and goes to get a cup of coffee. When he returns to the office, he is jumped and killed, and we see the screws going back into the air vent cover from the inside.

In Washington, Scully has lunch with a fellow FBI agent, Tom Colton. Colton is annoyed that his rise in the Bureau is progressing so slowly, citing cases of other agents who got promoted through luck. He pokes fun at Scully's assignment to the X-Files, and at "Spooky" Mulder, but Scully comes to her partner's defense. Colton then tells Scully he has a strange case which seems suited for Mulder's assistance: a series of murders in Baltimore with a common feature--no visible point of entry. In all cases, the victims were found in locked rooms, and each victim had his or her liver ripped out. Colton asks for Scully's help; he thinks solving the case is his ticket to promotion, and tells Scully she might not have to be "Mrs. Spooky" anymore.

Scully and Mulder go to check out the office where the businessman, George Usher, was killed. Scully tells Mulder that Colton asked for her help and not Mulder's due to his "spooky" reputation. Mulder meets Colton for the first time, and the meeting is terse. Mulder corrects Colton's crack about little green men as little gray men, citing the lack of iron in the diet of Reticulans as a motive for stealing the victims' livers; Colton, of course, thinks Mulder is nuts. Looking around the office, Mulder finds some hairs and becomes suspicious of the air vent as an entry point. Over Colton's protests, Mulder dusts and turns up a fingerprint.

Analysis of the strangely elongated fingerprint turns up something odd: the print matches that from the scenes of ten other murders, all with no entry point and extracted livers--but five were committed in the 1960s, and five in the 1930s. Mulder also mentions a case from 1903 involving an extracted liver that was before the advent of fingerprinting. He can see no evidence of alien involvement, but is struck by the fact that the prints match; he also figures there are two murders to go this time around. Scully is resistant to suggesting a 100-year-old serial killer and insists that the case is Colton's. Mulder sets up a compromise, where he will run his own investigation and stay out of Colton's way.

Scully presents a profile of the killer to Colton's team, suggesting a man age 25-35 suffering from a form of obsessive-compulsive disorder; she also thinks he may return to previous crime scenes. Colton's team decides to take her advice and stake out the old crime scenes, and offer to bring Scully aboard as something "a little more down-to-earth." Scully heads out to stake out the office building where Usher worked. In the middle of the night she is spooked by signs of movement, but it turns out only to be Mulder; he tells her that the killer gets off on getting into impossible places and that Scully is wasting her time. But as he's leaving, Mulder notices something moving through the ductwork in part of the building's service area.

Taken out of the ductwork and into custody is one Eugene Victor Tooms. Tooms is subjected to a lie detector test, indicating that he works for Baltimore's animal control department. The test results suggest that Tooms is not guilty, but on two questions inserted by Mulder (asking if he was over 100 years old and if he had visited one of the previous crime scenes in 1933), the results indicate that Tooms was lying when he answered no to both. Mulder is convinced that Tooms is the killer, and even Scully is suspicious of his presence in the office building late at night, but Colton and his supervisor don't want to hear Mulder's crackpot theory. Colton tries to offer Scully a way out of the X-Files, but she chooses to remain with Mulder.

Later, Mulder tells Scully he offered his theory even though he knew it wouldn't be believed just to mess with Colton's head. Scully thinks Mulder is being territorial, but Mulder counters that "you may not always agree with me, but at least you respect the journey." But Scully's curiosity is aroused, and she want to see what else Mulder has on Tooms. Doing some fingerprint work, Mulder takes Tooms' fingerprints on file and stretches them out; when the stretched print is compared with the one from the Usher crime scene and the old murders, they match. While Mulder can't explain the phenomenon, he is sure that a guilty man was set free. Elsewhere, Tooms stalks his fourth of five victims, taking out a businessman in his home by contorting his body and stretching in through a narrow chimney.

Colton and company arrive at the crime scene the following morning, desperate for a theory--or "any sane theory," Colton comments as Mulder and Scully walk in. Colton tries to block them, but Scully tritely tells Colton that they have authorized access to the crime scene and that blocking Mulder's investigation would look bad on his record. When Colton asks whose side she's on, Scully replies flatly, "The victim's."

Back at FBI headquarters, Mulder's search of birth records turns up a birth certificate for Eugene Tooms dating back to 1903. Scully reports that local police got into Tooms' apartment and found it to be a cover; he hasn't been there in weeks, and hasn't shown up for work since his arrest. Looking at the place of residence on Tooms' birth certificate and the address of the 1903 murder, Mulder thinks that Tooms murdered the man in the apartment above him. Scully, however, suspects that it was just one of Tooms' ancestors, and that the psychopathic behavior has just been passed from generation to generation. "So what is this, the anti-Waltons?" quips Mulder. He is concerned that there is only one victim to go and the next chance won't come until 2023.

Together, they begin scouring over old records, looking for clues. Mulder has turned up nothing--no sign that Tooms was ever born (after 1903), got married, or died--at least in Baltimore County. Scully has turned up one tidbit, which is the address of Frank Briggs, the detective who investigated the 1933 murders. The agents speak to Briggs, who was always bothered by the lack of closure in the 1933 case; he said the murders were chilling, reminding him of Nazi death camps. Briggs has saved all the evidence from his investigation, which he shares; he also says that in each case, family members found small personal effects of the victims missing. When identical murders occurred in 1963, Briggs was behind a desk, but he did some checking anyhow: he has pictures of Tooms in 1963, looking exactly as he does in the present.

Mulder and Scully go to check out Tooms' old place of residence, which now appears entirely abandoned. Searching around Tooms' apartment, Mulder finds a hole knocked out of a wall, leading into a coal cellar. Poking around, Mulder turns up a small shrine containing all of Tooms' trophies from his victims. In the corner, Mulder turns up a bizarre nest constructed out of newspaper shreds, saliva, and bile. Getting some of the stuff onto his hand just as Scully realizes what it is, Mulder quips, "Is there any way I can get it off my fingers quickly without betraying my cool exterior?" Mulder speculates that Tooms hibernates for 30 years and only awakes to take five livers for sustenance. On their way out, Scully pauses momentarily when she bumps into something, and then walks away. But above in the rafters, we see that Tooms has snatched Scully's necklace.

Mulder leaves two agents on stakeout at Tooms' residence, and says he and Scully will be back to relieve them in 8 hours. Back at FBI headquarters, an incensed Colton comes to talk to Scully; he is annoyed that Mulder is wasting his men on a stakeout, and with his supervisor's backup, has called the stakeout. Colton justifies his actions by saying that this is his way of climbing the ladder. "Then I can't wait until you fall off and land on your ass," replies an angry Scully.

Scully returns home, not aware that Tooms is following her. She leaves a message for Mulder expressing her anger at Colton, and then goes to draw a bath. Back at Tooms' apartment, Mulder arrives to find Scully absent, not aware that Colton has called off his stakeout. Looking through Tooms' trophy collection, Mulder spots Scully's necklace, and realizing she is the next victim, takes off for Scully's apartment. He tries to phone, but Tooms has cut her phone line. Back in her apartment, Scully notices slime dripping from an air vent and runs for her gun. Suddenly, Tooms bursts forth from a vent and grabs Scully by the ankle. Tooms and Scully struggle, but Mulder's arrival tips the balance, and the agents manage to handcuff Tooms. "You're not gonna get your quota this year," says Mulder.

In his retirement home, Frank Briggs is relieved to tears that Tooms was finally caught. Tooms, meanwhile, has been taken to a mental hospital, where he begins to build another nest. Scully reports that Tooms' muscular and skeletal structure are quite bizarre, and that his metabolism is below that of deep sleep. Mulder is left to wonder how safe people really are with Tooms on the loose. In the end, an orderly drops a tray through a narrow slot in Tooms' door, and Tooms immediately begins puzzling his way through the tight space, a smile on his face.

We open on a mother and her two children staying in a camper by a lake. The children are sleeping outside under a clear sky, while the mother sleeps in the camper. Suddenly, the ground begins to rumble and searing white light fills the sky. When the shaking stops and the light is gone, the woman comes out of the trailer, scorching her hand on a surprisingly hot doorknob. Her son Kevin is screaming for her, and her daughter Ruby has vanished.

In Washington, Scully meets with Section Chief Blevins, who is incensed that Mulder has applied for expense funding to travel to Sioux City, IA to chase down a tabloid headline of alien abduction. Blevins thinks that perhaps Mulder's interest has something to do with another X-File, which Blevins hands to Scully--the one regarding the abduction of Mulder's sister Samantha under similar circumstances. Scully doesn't believe Mulder's judgment is clouded, but recognizes it could be seen that way. Blevins is about to disallow the expenses, but Scully wants to talk with Mulder first.

Mulder's interest stems from the proximity of the disappearance to Lake Okobogee, a UFO hot-spot. The area was visited 4 times in 1967. It turns out that a Girl Scout who sighted the UFO in 1967 was Darlene Morris--the mother of the now-missing Ruby. The agents travel to Sioux City and meet Darlene and her son Kevin, who is remarkably sullen and quiet. Mulder, for his part, becomes lost in looking at a picture of Ruby as a little girl. Darlene says that she just wants her daugther back, and suspects alien abduction. Mulder asks to talk to Kevin for information.

Mulder finds Kevin (age 8) in front of a TV, where he's watching snow on a TV screen and writing down strings of ones and zeros on paper; he deflects Mulder's question about having nightmares. Kevin says the numbers are coming from the TV. At the local sheriff's office, Mulder has the numbers faxed over to the FBI for analysis. The sheriff seems convinced that Ruby just ran away from home, because she's done so before. Ruby was apparently a rebellious kid, often tangled up in sex and alcohol.

Returning to the car, the agents find a note on the windshield which says "I'm across the street. Follow me." The agents follow a young woman into a library. In a quiet corner, she tells them that Ruby was meeting with a boyfriend, Greg Randall, at the lake. Apparently, Greg got Ruby pregnant; she also tells them that Greg is a bartender at a local pub. Mulder and Scully check out the pub, which turns out to be a seedy biker place. The bartender hasn't seen Greg in weeks. Mulder notices the bartender has a flying saucer tattoo, and the bartender claims he's seen UFOs on Lake Okobogee when out riding his motorcycle; he also has a horribly burned and disfigured ear as proof.

That evening, Scully wakes up at 5:30 in the morning just in time to have her door busted down by government goons looking for Mulder. Apparently, the numbers Kevin was writing down from the TV are a classified defense satellite transmission. Unwilling to reveal the source, the NSA agents are ready to haul Mulder back to Washington. Scully, unaware of the NSA's lack of jurisdiction, reveals the source. "How can an 8-year-old boy be a threat to national security?" wonders Mulder.

The NSA descends on the Morris house and turns Kevin's room upside-down looking for evidence; his mother is hauled away. Having found more stacks of paper with ones and zeros, the NSA departs. Looking out from Kevin's window, Mulder notices that the roof of the family's trailer is severely and inexplicably scorched, as if touched by intense heat.

At the FBI field office in Sioux City, continued analysis of Kevin's papers have revealed some amazing patterns of information: a picture of DaVinci's universal man, a picture of DNA, and a fragment of Bach's Brandenburg concertos. "Almost like someone switching channels, huh?" notes Mulder. Mulder and Scully later catch up with Darlene Morris; Darlene is angry and refuses to cooperate with them further, only wanting her daughter back.

Mulder thinks that Kevin is the key to finding Ruby; he is functioning as a conduit for alien information. The agents head to lake Okobogee to look for evidence of an abduction. Mulder notices that the treetops are scorched and that beach sand has been fused to glass--both signs of extreme heat. Suddenly, Scully notices a wolf in the trees. Mulder gives chase, and the wolf leads him right to a body, buried under a shallow grave of rocks.

The police are called in to excavate the body, and looking through the wallet, the body turns out to be Greg Randall. Mulder turns up a note with a date and time for meeting with a Dr. Jack Fowler. He does a quick handwriting analysis of the note and the note left on his car windshield--both were written by the mystery girl the agents met in the library. A name, Tessa Sears, is turned up, and she is taken into custody. It turns out that Greg actually got Tessa pregnant, not Ruby, giving her a perfect motive for the killing. Mulder goes for the quick kill, saying that Tessa knew Greg and Ruby would be meeting; she killed Greg, and then Ruby. Tessa blurts out that Ruby wasn't there, and is thereby pegged for murdering Greg.

With a confession to Greg's murder, Scully thinks the case is closed, but Mulder is unwilling to give up, still having faith in his alien abduction. Scully tells Mulder to stop chasing after his sister, which earns her an angry retort from Mulder. The agents go to speak with Kevin again; when they arrive at the Morris house, they find the front door open, no one home, and piles of Kevin's data sheets laid out on the floor. Climbing up the stairs and looking down, Scully is shocked to discover that the data forms a picture of Ruby.

The agents drive back to the lake. On the drive over, Mulder confesses that every day he walked into his room with his eyes closed, praying that when he opened them that his sister would be returned. "I'm still walking into that room," he says. At the lake, the agents spot the Morris' trailer. The trailer is empty, but the agents find Darlene on a trail in the woods with a sprained ankle. Scully stays with Darlene, and Mulder chases down the trail after Kevin. He seems to be walking toward a bright light, and Mulder runs after him. Mulder grabs Kevin and pulls him to safety, just before a pack of bikers go speeding past on their motorcycles. "She's back," says Kevin.

Suddenly, Scully calls out for Mulder. She's found Ruby, unconscious but alive. Later, the agents meet with the Morris family at the hospital. Reading over Ruby's medical chart, Scully notices a variety of bizarre conditions that she can't put together--until Mulder pulls medical knowledge out of nowhere and then informs her that the symptoms are classic for prolonged weightlessness. Under questioning, Ruby cannot remember much except that "they" told her not to say where she had been. Darlene asks Mulder to leave the family in peace; she doesn't want her daughter to be a pariah like she became for her UFO story.

Back at FBI headquarters, Scully listens to Mulder's hypnotic regression tapes, where he recalls his sister's abduction. He remembers Samantha begging for help and his own paralysis. Elsewhere, Mulder sits alone in a church with a picture of his sister and sobs uncontrollably. On the regression tape, Mulder reports hearing a voice in his head telling him that his sister won't be harmed and will return. When the therapist asks if Mulder believes the voice, he can only reply unsteadily, "I want to believe."

At a remote research facility in Icy Cape, AK, two bloody and dirtied scientists wander the place with guns. One of them steps in front of a video unit and records and sends the message "We are not who we are." Suddenly the two scientists grapple with each other and end up with guns trained on each other. In a moment of realization, they change their minds and instead both commit suicide.

Mulder and Scully examine videos of the same team in earlier and happier days--an Arctic ice core drilling team. Apparently, the team had just set a record for depth in drilling into the ice. Everything was going perfectly, and then suddenly the "We are not who we are" transmission shows up and all contact is lost. Mulder says they were assigned the case because of brilliance or apparent expendability. Scully wonders if the men suffered some psychological breakdown, but Mulder says all the men were carefully screened to prevent such isolation disorders.

The agents fly to Nome, AK, where they meet up with three scientists who are familiar with the project: Denny Murphy (a geologist obsessed with listening to old football plays on tape), Lawrence Hodge (a medical doctor), and Nancy Da Silva (and a toxicologist). The scientists wonder why they are going to Icy Cape, and Scully realizes they haven't seen the last transmission. Suddenly, they are interrupted by the arrival of a tough-guy named Bear, who is flying them up.

The team arrives at the research facility late in the evening; the power is out and the interior is frigid. Bodies are strewn everywhere, and Mulder and Scully immediately begin to document the scene. Finding the ice cores in the freezer, Murphy concentrates on preserving the samples. Turning a corner, Mulder is attacked by a dog; Bear pulls the dog off of Mulder, but is bitten in the process. Hodge sedates the dog, and examination by Scully turns up black nodules under the dog's legs, indicative of swollen lymph nodes, and (according to Da Silva) classic signs of bubonic plague. Noticing a skin irritation on the dog, Scully is shocked to see something crawling under the dog's skin. Elsewhere, Bear begins spasming in the bathroom, and notices black nodules under his arms.

After some further examination, Scully concludes that the first three men were murdered, apparently by each other, and the last two men killed themselves. Bear, fearing for his own life but not telling anyone about his problem, asks if the black nodules are somehow connected. Hodge says it's impossible to be certain because the dog, upon reexamination, no longer had the nodules. Continuing to snoop around, Mulder finds data sheets; consulting with Murphy, the ice drilled turns out to be twice as deep as expected from satellite images, suggesting the team was drilling inside a meteor crater.

Meanwhile, Scully has turned up traces of ammonium hydroxide in the original team's body; while Da Silva has found no contamination elsewhere, Murphy has--in the ice. Under a microscope, Murphy has found a small, worm-like object in the ice core sample; Scully reports finding the exact same thing in the blood of the first team. This leads Murphy to speculate the organism grows larger and was somehow transmitted to the researchers. Bear and Hodge both want to leave, but Mulder wants to take quarantine procedures.

To be on the safe side, Scully and Hodge insist on blood and stool samples, as well as visual inspection for black nodules. An increasingly irate Bear refuses to play along and storms out, insisting that he's leaving. The rest of the group votes to examine Bear, and if he's clean, then they'll leave. Mulder pulls out his gun to enforce the point. Bear agrees, and then attacks Mulder without warning. The others tackle him and restrain him, and they sight a worm crawling under his neck. Hodge tries to cut the worm out, which ultimately requires a pair of forceps. The worm is safely isolated in a jar, but Bear dies. Mulder radios for help and quarantine, but a winter storm has arrived early and the team now has no pilot.

Scully manages to isolate one live worm from the remaining bodies, making a total of two live speciments, both of which seem to thrive in ammonium hydroxide solution. The worm in the dead body was found in the hypothalamus, which is the endocrine organ responsible for secreting acetylcholine, which regulates violent behavior. Mulder takes this to mean that the worm induced the previous team of five to kill each other.

Later, Mulder finds Scully in an auxiliary area, checking on the bodies; neither of them is able to sleep. Scully wants to waste no time trying to kill the worm, but Mulder thinks that might be a bad idea. Given that the worm was found in subzero temperatures over a meteor crater and thrives in ammonia, he suspects it may be a lifeform from outer space. As usual, Scully thinks Mulder is nuts; she is staggered at how quickly the worm could infect the rest of the world, and she doesn't want to end up in a showdown with Mulder involving guns and suicide, just like the previous team.

In another room, the scientists overhear Mulder and Scully arguing, and speculate that the FBI knew what was in the research facility all along. Hodge is concerned about Bear's infected blood having splattered on Scully--until Da Silva points out that it got on Hodge as well. Going to see what the argument is about, Hodge questions if Scully is becoming overly irate. Before the situation boils, Mulder tells everyone to calm down and to sleep, and not to turn on one another.

To prevent crisis, the group strips down and examine each other for spots; everyone turns up negative. Resting a little easier, they head off to the bunk rooms to sleep. Before turning in, Mulder reminds Scully that the spots on the dog went away. Upon entering her room, Scully becomes panicky, moves a desk in front of her door, and sits nervously on the floor.

Waking with a start in the middle of the night, Mulder leaves his room, gun in hand, to have a look around. In the research laboratory, he finds blood dripping out of the freezer, and when he opens it, Murphy's body spills out of it. Scully and the others awaken and walk out to find Mulder holding the bloody body in his arms. Hodge immediately accuses Mulder of the killing, but Mulder insists it was one of the others. Hodge and Scully want to test Mulder for infection, and Mulder thinks Hodge will mess with the results. When Mulder refuses to drop his gun, Scully pulls her gun on Mulder. "Mulder, you may not be who you are," she says. Mulder finally relents, and with some uneasiness, Scully locks Mulder in a separate room. "In here I'll be safer than you," Mulder says flatly.

Returning to find Da Silva and Hodge asleep, Scully tries to look at the back of Da Silva's neck, when she is suddenly stopped by Hodge, which wakes Da Silva. Hodge questions Scully having a gun, which leads Scully to remove the clip from her gun and Mulder's and toss them both into the snow. Hodge tries to exlude Mulder from the group, but Scully counters that even if Mulder is infected, it isn't his fault. Scully mans the radio, but is unable to reach anyone.

While continuing research on the parasite, Da Silva accidentally mixes two samples of infected blood. The two get into a heated argument, but Scully looks in the microscope and notices that the larvae of two different worms killed each other. Looking in the freezer, Scully and Hodge notice that the two worms become extremely combative when placed in close proximity to each other. As a test, they drop a worm into the infected dog. Within hours, both of the worms in the dog are dead and passed in its stool.

Scully goes into Mulder's miniature prison to talk to him and explain the situation. Mulder explains that he was perfectly willing to be examined until Scully drew a gun on him. Finally relenting, Scully examines Mulder's neck and finds nothing. Irritated, Mulder grabs Scully and examines her neck as well. Outside, Da Silva speculates that Mulder will talk Scully out of implanting the worm. When Scully explains the situation, Hodge agrees that everyone should examine everyone else. Suddenly, Hodge grabs Mulder from behind and holds him down. Meanwhile Da Silva locks Scully in Mulder's former prison. Just as Da Silva is about to drop the worm in Mulder's ear, Hodge notices that Da Silva is the one who's infected.

Da Silva runs, and Hodge scoops up the remaining worm. After Mulder and Scully restrain Da Silva, Hodge puts the last worm in her ear. After convulsing around, Da Silva calms down. The team is eventually evacuated, and Da Silva is put into quarantine; Mulder, Scully, and Hodge all come up clean. Mulder wants to go back to the site, but Hodge tells him that the military torched the whole facility.

"It's still there, Scully," says Mulder. "200,000 years down, in the ice." Scully's only reply is, "Leave it there."

The episode opens with a retrospective from the 1970s, recounting the successful Viking Observer mission to Mars. The joy at the discovery of water is revealed, as is a photograph of the infamou "Face of Mars." In an interview with Project Director Marcus Aurelius Belt, a former Gemini astronaut, Belt says that the "Face" is just an anomaly, a trick of light and shadow, not an indication of alien life. We then cut to Belt returning to his apartment. He sleeps uneasily, having dreams of being attacked by "something" during his Gemini space walk. When he awakens, a ghostly form that looks like the "Face" attacks him in his bed.

We then cut to the present day, where Belt is now director of the space shuttle program. In the midst of a launch, the liftoff is stopped just three seconds before ignition due to an unforseen fault. Two weeks later, Mulder and Scully wait in Washington to meet with someone from NASA who wished to speak anonymously. Their contact turns out to be Michelle Generoo, who is the communications director for the space shuttle program. She suspects that there is a saboteur at work inside NASA, and explains the scrubbed launch from two weeks ago. She shows Mulder and Scully pictures of scoring in an auxiliary power unit that were sent to her anonymously, and further says that given the strength of the material, it would be impossible for anyone to do that much damage. Michelle has taken matters into her own hands, as she has a personal stake: there is another launch window tomorrow, and her fiancee is the mission commander on the shuttle.

Mulder and Scully travel to Houston and meander through the NASA facilities. Scully wonders why anyone would want to sabotage the shuttle; Mulder says there's no better symbol of American superiority for terrorists to attack. He also suggests that other failures (the Mars Observer, the Hubble Telescope) may be part of a conspiracy by the government to prevent people from knowing about the existence of alien civilizations. Mulder and Scully meet with Colonel Belt; Mulder expresses that Belt was his boyhood hero, having always been a fan of the space program. Scully shows Belt the picture given to her by Michelle, and questions Belt's knowledge of it. He responds strongly, saying there is no chance of sabotage and he has full confidence in his people. He is so sure of his safety, and so intent on delivering his payload, that he will not delay the launch. He does, however, allow Mulder and Scully to observe the launch from Mission Control.

Mulder and Scully talk with a shuttle scientist, who claims to have never seen the picture produced by Michelle, and never ordered the tests indicating the damage. He says that to redesign the power unit would take months and cost millions, but stops short of saying that safety was compromised to keep the program moving. He says that the ultimate decision to fly is made by Colonel Belt. Scully suspects that Belt knows more than he's telling.

That evening, with Mulder and Scully watching from Mission Control, the shuttle successfully lifts off and makes orbit without a hitch. Mulder and Scully prepare to head home, but they are snagged by Michelle at their hotel; communications have been lost with the shuttle. Driving back to the space center in the driving rain with Mulder and Scully following, Michelle sees a ghostly "Mars Face" come at her out of the fog; startled, her car careens off the road.

Mulder and Scully get Michelle out of her car; fortunately her injuries are not severe. She explains what she saw, but is intent on getting to Houston. The three arrive at Mission Control and find Colonel Belt mysteriously absent. Radio communication is now possible, but the shuttle has a problem: it cannot rotate away from the sun, and the cabin temperature is rising. A controller thinks that the shuttle telemetry is somehow being jammed on the ground; tracing leads them to the center's data banks. In the data center, Mulder and Scully only unearth a frightened scientist, who insists he works here and doesn't know anything.

Back in Mission Control, Belt has finally arrived; in a risky maneuver, he breaks ground contact with the shuttle and allows the shuttle to try and maneuver itself. Fortunately, after a minute of tense waiting, the maneuver works. Later, we find Belt in the washroom; when he looks in the mirror, his face seems to be distorting oddly.

At a press conference, Belt reports that the mission is running without incident. Michelle suspects that Belt is simply putting payload delivery ahead of astronauts' lives--to do otherwise would invite Congressional shutdown; disgusted, she walks out of the press conference. Mulder catches up with Belt to question him. Belt says that astronauts used to be front page news; "you only make the front page today if you screw up," says Belt. Returning home, Belts heads off to sleep; while lying in bed, his face repeatedly distorts into something looking like the "Mars Face". Then, suddenly, a ghostly form rises up and leaves his body.

Moments later, the shuttle crew reports bumping noises, which ultimately turn out to be a severe oxygen leak. Mulder recalls that the exact same thing happened to Belt on his Gemini mission. In the midst of the crisis, however, Belt is nowhere to be found. Mulder and Scully go to find Belt; he turns up in his apartment, claiming illness. At Mission Control, Michelle is just about to bring the shuttle home when Belt arrives. He orders the astronauts to don their space suits, depressurize the cabin, and deliver their payload. Infuriated at the risks Belt is taking (despite his personal knowledge of this kind of situation), Michelle walks out of the room.

Outside, Michelle expresses her disbelief that Belt is putting payload before lives to Mulder and Scully; Scully agrees. Mulder, however, can't understand why Belt would cause sabotage and then save his men time after time. He argues that the space program would be killed whether the payload was delivered or the astronauts died. Even if Belt is the saboteur, he may be the only one who can get the astronauts down alive.

The astronauts complete their payload delivery, and Belt orders them home. Just then, the astronauts report a ghostly form "attacking" the ship. Belt recoils in horror and begins screaming uncontrollably. Elswhere, Mulder and Scully hurriedly search through piles of NASA records. Scully turns up a diagram identical to the one given anonymously to Michelle--with tests ordered by Belt before the launch. Mulder has found tests indicating a faulty O-ring on the shuttle Challenger--and the tests were also ordered by Belt, a week before the ill-fated launch. Just then, Michelle enters and reports that Belt has collapsed in his office.

Mulder tries with marginal success to focus Belt's pain so that he can speak. Michelle leaves to bring the shuttle down, but Belt tells her that she can't: the fuselage, covered with heat-absorbing tiles, is damaged. Belt says he didn't sabotage the shuttle, but he couldn't stop "them." Belt's face mutates again into the "Mars Face," and Michelle identifies it as the face she saw before her car wreck. Michelle goes to bring the shuttle home, and Belt is taken to the hospital. On the way out, Belt tells Mulder that the shuttle needs to change its re-entry trajectory or it will burn up. Michelle relays the information in the nick of time, and the shuttle makes a successful landing in New Mexico. Later, at a press conference, Michelle is forced to tell reporters that everything happened "without incident."

That evening, in his hospital bed, Belt begins morphing into the "Mars Face" again. Fighting off the alien spirit, he crashes through his window and plunges to his death. Mulder, for one, is convinced that Belt was possessed by something he saw in space; he suspects Belt never fully knew of his possession, but once he did, he tried to fight it. He was both the saboteur and the savior; he may have been the one to send Michelle the pictures of the faulty power unit. Mulder and Scully attend Belt's funeral at Arlington National Cemetery, as does Michelle; whatever happened to Belt, it is now at rest.

The episode opens around midnight in the town of Townsend, Wisconsin. A state trooper spots a forest fire in progress. He attempts to radio the fire in, but finds that his radio is not functioning. He begins walking towards the fire to investigate. Elsewhere, at Cheyenne Mountain, Colorado, the US military's space surveillance spots an unidentified object on their radar. The craft's trajectory is all over the place, and then it crashed in Townsend at a speed of over 800 miles per hour. The radar operator wants to log the incident, but her commanding officer tells her simply to log it as a meteor strike; he then makes a call on his cellular phone and reports a confirmed "fallen angel" and mobilizes "Operation Falcon." Back in Townsend, an invisible figure streaks by the state trooper; suddenly, everything goes white as the figure attacks the trooper.

Mulder arrives in Townsend the following day; the official story in the news is that there was a major toxic chemical spill in the forest, and the Army is cleaning the spill. Mulder flashes back to a conversation with Deep Throat from the day before; Deep Throat tells Mulder about the fallen angel and the mobilization of Operation Falcon, under Colonel Calvin Henderson, the Army's UFO "reclamation" expert. Deep Throat says that Mulder has about 24 hours before all the evidence has been cleared from the crash site. Cutting back to the present, Mulder works his way into the forest to the crash site, only to find it surrounded by a laser perimeter fence. Mulder eventually finds his way inside by sneaking in on a truck; he overhears Colonel Henderson telling his troops to prepare to use live rounds. That night, Mulder watches over the crash site and sees men in heavy suits spraying the area with some kind of chemical smoke; he takes pictures, but then gets captured before he can escape.

In custody, Colonel Henderson exposes all of Mulder's film and then berates him at length for violating a government quarantine; he also tells him to forget whatever he saw. Mulder is put in a holding cell. In the next cell over is long-haired, bespectacled Max Fenig, a member of the National Investigative Committee of Aerial Phenomenon (NICAP). Max was imprisoned trying to get a glimpse of things, but didn't get far before being captured. Later that night, Scully arrives to collect Mulder from his cell; Max has been released while Mulder was sleeping. Scully is incensed; Section Chief McGrath has ordered a full investigation of Mulder and wants to shut down the X-Files. Scully tells Mulder that he hasn't seen a UFO; the cover story about the spilled chemicals is simply because there is a downed Libyan jet carrying a nuclear warhead in the area. Mulder finds that idea preposterous. "That story happens to be highly classified," says Scully. "A highly classified lie," replies Mulder. Later that morning, we see the perspective of the invisible creature; it approaches the laser fence and then takes off at top speed away from the area.

Mulder wants to stay and investigate; Scully says she is under orders to bring him back, not help him out. Mulder returns to his hotel room to find it totally ransacked. The agents hear someone in the back room and catch Max Fenig trying to worm his way out the bathroom window. Max just wanted to know if it was really Mulder; NICAP has been following his career closely and is very interested in his work with the X-Files. They are also aware of an article he published in Omni Magazine under the pseudonym M.F. Luder. Excited, Max leads Mulder and Scully to his trailer, which is decked out with a ton of expensive communications equipment. Max shows Mulder some of his crop circle photos, and Mulder elaborates on why he thinks they're a fraud. Looking around, Scully notes prescription bottles full of Dilantin and Mellaril. Max then plays a tape of a radio conversation with the deputy from the beginning of the episode; then he fast-forwards to the arrival of the fire crew, which finds the deputy dead.

Mulder and Scully visit an emergency shelter set up by the town; they go to speak with Mrs. Wright, the deputy's wife. However, she is upset and reluctant to talk. She is distraught because her husband's body won't be released; the government has threatened to withold her pension if she talks to anyone. Suddenly, power fails in most of the town. The army detects a shape moving on their infrared sensors, and Colonel Henderson sends his men in to "search and destroy." At the same time, Max picks up an extremely high frequence noise on his radio scanner.

Searching out the invisible alien intruder, part of Henderson's team is attacked in the same bright white flash of light. Elsewhere, Mulder and Scully go to the county hospital, where they find the ER doctor unwilling to talk about Deputy Wright--apparently he was also pushed around by the government. The doctor finally caves in and reports the deputy and the fire crew were brought in dead with severe burns; Mulder thinks that the burns were caused by ionizing radiation. Just as Mulder and Scully are leaving, members of Henderson's team are wheeled into the hospital with severe burns all over their bodies.

Colonel Henderson tries to restrict Mulder's access; he thinks that Henderson is hunting down the alien, which is forcing it to attack. The ER doctor tells the colonel that Scully is staying, because she's a doctor and he needs help. Henderson finally concedes, but has Mulder dragged out of the ER. Later that morning, Mulder returns to his hotel and decides to go speak to Max. He goes into Max's trailer and finds Max sprawled on the floor in the midst of a seizure. When he calms down, Max is surprised that he had a seizure; he hasn't had one in 7 years, since he started on medication. Max says he started his bouts with epilepsy at the age of 10; he would have seizures and wake up with no idea of how he got where he was. As Max lies down to sleep, Mulder notes in interesting triangular scar behind Max's right ear; later, Mulder reads over reports from the X-Files and finds that similar scars have been reported by UFO abductees.

Scully returns, and says that only of two of Henderson's men actually survived. Mulder tells Scully about Max's incision; he thinks that Max Fenig may be an abductee. Scully tells Mulder that Fenig may be unbelievable at best; he is taking anti-convulsive drugs, but he is also taking Mellaril, which is only used to treat schizophrenia. Scully finally relents and agrees to look at Max's scar.

Back at Cheyenne Mountain, the military tracks another unknown inbound, much larger than the first. The duty officer tells the radar operator that it's simply another meteor. The radar operator retorts, "Well, sir, the meteor seems to be hovering over a small town in eastern Wisconsin." Meanwhile, the invisible alien creature breaks into Max Fenig's trailer and notes the scar on his ear. Suddenly, Max's ear begins to bleed, he rolls over, and his eyes snap open.

When Mulder and Scully get to Max's trailer, he's gone; all that seems to be left is a bloodstain on his pillow. Listening to Max's radio, Mulder hears the "Falcon patrol" reporting an "unidentified trespass at the waterfront." Scully wants to go to the airport and home, but Mulder is unrelenting; he is concerned that Henderson is aware of Max's status as a UFO abductee and wants to use him as some kind of bait.

Mulder and Scully head to the town waterfront, where they find some of Henderson's men dead, burned almost beyond recoginition. From a nearby warehouse, screams are heard. Mulder and Scully go inside and find Max holding his bloody ear saying, "It hurts, it hurts, they're coming for me..." Outside, helicopters are heard buzzing overhead and Henderson's team is descending on the waterfront like the plague. Scully goes outside to investigate and is captured by Henderson's men. Henderson's men set up positions with missile weapons to blow the warehouse up--with Mulder, Fenig, and an unknown third form inside. Mulder tries to get Max to move; just then, the invisible form moves forward and throws Mulder across the room. Mulder turns to find Max suspended in the air, bathed in a strange blue light. There is a flash of white, and Max disappears.

Outside, Henderson's men now only detect one figure inside. Henderson's men blow the warehouse door open and find only Mulder inside, scooping Max's NICAP hat off the floor. Henderson has Mulder arrested and orders his men to scour the area.

Mulder and Scully return to Washington and go before the review board. Scully is asked questions pointing to Mulder's obvious culpability in misuse of government materiel; she is denied to opportunity to make a statement on Mulder's behalf. Mulder goes before the review committee on crutches; the dialogue between Mulder and Section Chief McGrath is explosive. McGrath goes with the official government line; even Mulder's new evidence is not enough. "How can I disprove lies that are stamped with an official seal?" cries Mulder. He closes by saying that too many people know what's going on and the truth will get out, because "no government agency has jurisdiction over the truth."

Later, McGrath meets outside with Deep Throat; McGrath is outraged that Deep Throat has countermanded the committee's decision to get rid of Mulder and close the X-Files for good. Deep Throat says it's better to put up with Mulder's insubordination than letting him reveal to the wrong people what he knows--or thinks he knows. "Always keep your friends close, Mr. McGrath, but keep your enemies closer."

In Greenwich, Connecticut, young Teena Simmons is found clutching her teddy bear in her driveway by her neighbors. Concerned, the neighbors take Teena to find her father, Joel, who is in the back yard. When they reach him, he is dead and blue, with two puncture wounds in his neck.

Looking over the evidence in Joel Simmons, Scully sees that he died from blood loss--over four liters worth, even though his daughter had left his side for only 10 minutes. Mulder notes remarkable similiarities to this case and cattle mutilations--the jugular vein is punctured and the heart pumps blood out--a phenomenon known as exsanguination. Mulder also notes that Simmons' body was filled with digitalis, a paralytic agent, which explains the lack of signs of a struggle.

The agents travel to Greenwich and meet with Teena, who is being held by social services (since her mother had already died two years ago from cancer). Teena is remarkably quiet, answering most questions with a nod or a shrug or a word. As far as she knows, no one really had a motive to kill her father. When asked by Mulder, Teena says that she saw "red lightning," and says that the "men from the clouds" were after her father. When asked why, Teena (age 8) flatly replies, "They wanted to exsanguinate him."

Scully receives a phone call, and the agents learn there has been another, identical murder all the way across the country in San Francisco--this time a man named Doug Reardon. Every detail is the same: puncture wounds, exsanguination, and digitalis poisoning. Factoring in the time difference, Mulder notes that the murders even occurred at the same moment. Scully suspects two serial killers working together, but Mulder discounts that as unlikely. He does, however, think the Reardons' daughter will remember "red lightning."

That evening in Greenwich, Teena rouses from bed, thinking she hears a noise at her door. Sensing someone outside, she blocks the door with a chair and then tries to escape through a window. Failing that, she hides under herbed. After waiting a moment, she emerges, only to be grabbed. A social worker arrives moments later to find a scene of disarray and an open window.

Heading to meet the Reardons, Scully and Mulder mull over the disappearance of Teena, and the fact that roadblocks have turned up nothing. Much to the agents' shock, when the Reardons' daughter, Cindy, answers the door, she looks exactly like Teena. Mulder immediately notices her odd behavior--choosing to watch the news over cartoons. Cindy's mother reports that Cindy was not adopted; when shown a picture of the Simmons family, she is shocked to learn that Cindy looks like Teena. The agents then learn that Cindy was the product of in vitro fertilization.

Worried that Cindy might be abducted, Mulder hangs back to keep an eye on her while Scully heads to San Francisco to visit the fertility clinic used by the Reardons. A little digging by Scully reveals that both the Reardons and the Simmons used the same fertility clinic, and had the same doctor--Sally Kendrick. With some hesitation, the facility's director tells Scully that Kendrick was a brilliant doctor, but there was some concern that she was tampering with fertilized eggs--unauthorized eugenics experiments. Kendrick was fired and the director ordered a federal investigation, but the request was denied. Kendrick disappeared into thin air.

Back at their hotel, Scully brings Mulder up to speed; Mulder now thinks that Kendrick may be working to erase her experiments, but that she would still have to have an accomplice. The phone rings, and Scully answers, only to get a few clicks--Deep Throat's signal. Mulder rushes Scully out of his room and then goes to meet Deep Throat. Deep Throat then reveals to Mulder the details of the highly-classified Litchfield Project: Cold War fear that the Russians were tampering with eugenics to develop superior soldiers led the United States to respond in kind. Genetically identical twins were raised up--the boys called Adam, the girls called Eve.

Mulder and Scully travel to an institute for the criminally insane, where (with clearance provided by Deep Throat) they get in to meet Eve 6. The agents find Eve 6 sitting in a dark cell (since she reacts violently to light); when they illuminate her face with a flashlight, she is a dead ringer for Sally Kendrick. She explains she is in chains because, "I paid too much attention to a guard. Bit into his eyeball. I meant it as a sign of affection." She says all the Eves are very bright and wagers that her IQ is over 260. She says that most of the Adams and Eves are dead, prone to suicide, but that Eve 7 and Eve 8 managed to escape. The Eves were born with extra genes, which heighten their strength, their intelligence--and their psychosis. Eve 6 says she is visited now and again by Litchfield scientists who are trying to determine what went wrong. For proof of her story, Eve 6 shows a photograph of all the Eves together--and they look just like Teena and Cindy. Mulder realizes that Sally Kendrick was trying to continue the Litchfield experiments by cloning herself.

Mulder and Scully return to keep watch on the Reardon house. Mulder thinks that the escaped Eve 7 and 8 (one of whom goes by the name Sally Kendrick) are working in tandem to keep Teena and Cindy "in the family" by killing off the parents; he figures the girls are just innocent pawns. With Scully watching, a figure emerges from the Cindy's closet and grabs her. Mulder and Scully spring to action, but Scully is quickly knocked out. Mulder stops Eve 7 (or 8), but is forced to back off when the Eve producees a gun and puts it to Cindy's head.

Kendrick returns with Cindy to a hotel north of San Francisco, where Teena is already being held. From the moment Teena and Cindy meet, they seem to have an unspoken mental communication. Back in San Francisco, Scully has turned up Kendrick's car at the airport, but Mulder has a report of the girl turning up in a hotel north of the city. What seals it for Mulder is when the girl reportedly told the hotel manager to "use chlorine to eradicate the dinoflagellates in the swimming pool. Does that sound like someone you know?"

Back at the hotel, Kendrick reports that she searched for the remaining Eve without success. However, her continuation of the Litchfield work met without success because the girls developed murderous tendencies even earlier than the original batch of Eves. When asked questions, Teena and Cindy tag team, each taking a sentence, as if completing each other's thoughts. They "just knew" of the other's existence, and killed their fathers because they weren't really their fathers. Kendrick says that with medication and therapy, the girls can grow up normally, like she did. Suddenly, Kendrick begins convulsing, realizing too late that Teena and Cindy have poisoned her soda with digitalis--more than enough to kill her. Kendrick grabs a knife and tries to kill the girls, but dies before she can succeed.

Mulder and Scully arrive on the scene to find Kendrick dead and the girls cowering in the corner. The girls report that Kendrick and another woman who looked just like her--Eve 8--tried to kill them. Scully suspects that the sweet taste of digitalis in soda would never have even been noticed; Mulder recalls the Eves were prone to suicide. Mulder and Scully take the girls into custody.

Traveling down the road, one of the girls complains that she has to go to the bathroom, so Mulder pulls over at a truck stop. Mulder orders two diet sodas, and (at Teena and Cindy's insistence) two regular sodas while he waits. While one of the girls distracts Scully, and when Mulder heads to the bathroom, the other drops digitalis into Mulder and Scully's sodas. Mulder and Scully both notice that their sodas take remarkably sweet and syrupy for diet. Mulder goes back inside when he realizes he's left his keys behind and finds traces of digitalis on the counter.

Mulder tries to discreetly warn Scully that Teena and Cindy poisoned their sodas, but the girls run at the first sign of trouble. They elude Mulder's search for a while. When Mulder catches them, the girls scream for help, and an unsuspecting trucker pulls his shotgun on Mulder, giving the girls time to escape. The waitress notes a bunch of schoolkids leaving on a bus, and the agents give chase. Finally, the girls see the agents' car pulling away. Feeling secure, they step out of hiding, only to fall into the hands of the waiting Mulder.

Mrs. Reardon is greatly saddened, but in the end realizes that Cindy was never her daughter. She tears up her family portrait and throws Cindy's picture in the fire. Back at the insane asylum, Teena and Cindy (now Eve 9 and Eve 10) are housed next to Eve 6. "So nice to have company," remarks Eve 6. At the front desk a doctor checks in to see the Eves--a doctor who looks identical to Kendrick. Teena and Cindy greet her. "Hello Eve 8. We've been waiting." Eve 8 asks, "How did you know I'd come for you?"

Eve 9: "We just knew." Eve 10: "We just knew."

We open on an English estate near London. A British Member of Parliament heads off from his home on the way to work. On the way, he offers a pleasant good morning to his gardener, Cecil L'Ively. Suddenly, the Parliament man bursts into flames and collapses, while L'Ively casually watches.

In Washington, Mulder and Scully have just emerged from testifying in a case; Mulder notes dryly that chasing down aliens usually precludes prosecution. When the agents reach their car, Mulder is surprised to find the doors unlocked and a tape waiting for him inside. Dropping the tape into the car's cassette player, a woman's voice descibes how a British Member of Parliament was killed by getting into his car, playing an unmarked tape (which armed the plastic explosives under the car), and then opening the door. On cue, the car door pops open, causing Scully to gasp; but it turns out to be only an "old friend" of Mulder's, a Scotland Yard detective named Phoebe Greene. Mulder seems a little annoyed to see her again, saying that his sense of humor was about the only thing she didn't "drive a stake through" at Oxford ten years ago. Phoebe kisses Mulder, which leaves Scully dumbstruck.

Phoebe has come to the US to protect a traveling British dignitary, Sir Malcolm Marsden. Apparently, someone has been targeting British nobles and Parliament members; the man sends love letters to the victim's wives, and the victims are always mysteriously burned alive. Phoebe has brought the problem to Mulder's attention, who promises to run everything by the FBI arson specialists. After Phoebe leaves, Mulder confesses to Scully that he was romantically involved with Phoebe in the past, and that he got in over his head. Scully thinks that Mulder is still smitten by her, but Mulder says he's merely extending professional courtesy. "Oh, is that what you were extending?" Scully deadpans.

Mulder, Scully, and Phoebe run crime scene photos by Agent Melvin Beatty, an arson specialist. Beatty is fascinated by the fires, and suggests that some kind of accelerant must have been used to start them; he points to some recent unexplained arsons in the US. But Phoebe says that no traces of any kind of fuel was found at the scene of any of the crimes. Mulder thinks that this may be a case of pyrokinetics, people who can control fire with their minds; Beatty says he has seen fire do odd things, but nothing in violation of physical laws.

On Cape Cod, MA, a house painter is seen at work on an interior room as Sir Malcolm Marsden arrives with his wife and two children for their vacation. The painter, watching the scene, pops a cigarette out of his case; it lights spontaneously in his mouth, and we see that the painter, now minus a beard, is Cecil L'Ively. Coming downstairs, the painter introduces himself as Bob, the house's caretaker. Bob says he's been working hard to clean the house up for the Marsden's arrival, and offers to help in any way possible. Heading up the stairs, Sir Malcom's wife notes a portrait on the landing that looks remarkably like her. Outside, Bob finds the family's dog digging in the back yard; he kicks it away and threatens it. In the hole, we see that the dog has dug up part of a body buried in the yard.

At the X-Files office, Mulder says the he will pursue the investigation without Scully's help; he's taking her off the hook, not wanting to subject her to "Phoebe's mind games." Mulder confesses that he is terribly afraid of fire, recalling a childhood incident where his best friend's home burned down, and saying that he's had terrible nightmares about being trapped in a burning building ever since. He says that Phoebe is all too aware of Mulder's phobia, and is manipulating him. Back on Cape Cod, while Sir Malcolm's wife works in the kitchen, Bob watches lustfully from a distance, admiring. Hearing coughing, Bob heads to the back of the house and finds the Marsden family driver sitting by the car; Bob offers to buy the driver cough medicine when he goes into town that night. When Bob does go into town, he heads immediately to a bar. He is seen with a bottle, which the woman next to him says he can't bring into a bar. Bob offers to light the woman's cigarette, and produces a flame from the tip of his finger. The woman is impressed enough to tell her friends, but when she turns back, Bob's entire arm is ablaze. "Care for a light?" he quips, and then touches the entire bar on fire.

In Boston, Mulder and Phoebe head to a hospital, where victims from the bar fire have been taken. Witnesses have said that a man caught on fire, and the fire burned so hot that the whole place burned down, even though a fire station was right across the street. Mulder and Phoebe meet with the woman who talked to Bob, and she recounts her story, also offering a physical description of Bob. She also remembers that he had an English accent. Outside, Phoebe notes Mulder's deft technique in finessing information from an interviewer; Mulder snipes back and says that he perfected his technique in his relationship with Phoebe. Realizing he's being unnecessarily cruel, Mulder apologizes. Phoebe says that a few "youthful indiscretions" should be forgotten; Mulder points to the fact that he has a photographic memory. Phoebe then recounts a certain "youthful indiscretion" on top of Sir Arthur Conan Doyle's tombstone, but Mulder insists on sticking to the case. He's not convinced the burning man is dead, since no body was found.

Back in Cape Cod, Bob notes with some delight that the Marsden family driver is still coughing, sicker than he was the previous night, looking at the bottle of "cough syrup" he bought. Back in Washington, Scully is working to profile the arsonist. Though no accelerant has ever been found at the scenes, the nature of the crimes suggests that the arsonist was personally close to all of the victims. He is probably under age 25 and impulsive. On Cape Cod, Bob does a "magic trick" for the Marsden children, Jimmie and Michael: he takes a cigarette, makes it disappear from his hand, and then produces it from his ear, already lit.

Scully, meanwhile, goes to speak with Agent Beatty again. Scully wonders if it might be possible to hide the fire accelerant by diluting it into hand creme or another household product. Beatty admits that it's possible, but that there would still need to be a way to ignite the accelerant. Back on the Cape, Bob's "magic show" is progressing, and he now spontaneously lights cigarettes in his mouth. He offers the kids a puff on his cigarette, but they refuse. Just then, Marsden's wife comes out of the house and tells Bob that their driver has become too ill to work. Bob offers to drive the Marsdens to a social function in Boston that evening, and to watch their children during the event. Meanwhile, Scully's profiling continues; arsonists are typically sexually fixated on women they couldn't ever hope to have. She's convinced the arsonist has followed Sir Malcolm to the US, and that he will strike again. Scully begins checking immigration records for clues.

In Boston, Mulder says that this arsonist seems to have more than just pyrokinetic powers, since he lit himself on fire and survived; Phoebe agrees, which startles Mulder, who is more used to Scully's skepticism. Together, Phoebe and Mulder agree that the social event the Marsdens will be attending, a party in their honor at a hotel, would be a perfect place to set a trap for the arsonist. That night, Mulder arrives at the hotel and checks into a room reserved to Phoebe; he gets a call from Scully, who says she has information and is coming up to Boston to meet him. Shortly thereafter, the Marsdens arrive with Phoebe and the driver, Bob. Phoebe thinks that Bob is the regular driver, who is supposedly a capable bodyguard. Inside the hotel, Mulder lingers outside the ballroom in a tuxedo, until Phoebe privately catches up with him.

Convinced that the arsonist isn't going to show, Mulder and Phoebe do a slow dance outside the ballroom. Scully arrives moments later, and from a distance, she cannot help but roll her eyes when Mulder kisses Phoebe again. Looking over her shoulder, Scully notes Bob standing there, but when she looks again, he's gone. Just then, Scully rushes to an alarm panel and notes that a fire has broken out on one of the hotel's upper floors. She brings the information to Mulder and Phoebe, breaking up their intimate moment; Phoebe realizes that the fire is on the same floor as the Marsden children.

Mulder dashes upstairs to rescue the kids, but his fear of fire and smoke inhalation quickly overwhelm him. The Marsden children, however, are carried to safety by Bob the caretaker, who is hailed as a hero. Mulder is later rescued by firefighters. Taken up to Phoebe's hotel room, Mulder slowly recovers, finding Scully (and not Phoebe) waiting for him. Scully is curious about the driver, but Phoebe arrives and says that his record is clean; Scully wonders how the driver rescued the kids when she saw him in the lobby just seconds before the fire broke out. Phoebe says the Marsdens are leaving the country in two days, and that she is leaving as well. When she exits, Scully unloads her collated information on Mulder.

She's compiled a list of possible accelerants, and has checked through employment records to find any servants or workers the murder victims had in common. Only one name, that of Cecil L'Ively, turns up more than once. A little digging showed that L'Ively was a model citizen--right up until he died in a tenement fire in 1971. The name also shows up in connection with some cult killings in the 1960s, and again when issued on a recent visa to the US. Realizing that Phoebe and the Marsdens may be in danger, Mulder takes off for Cape Cod, while Scully works to have a composite sketch of the man who burned down the bar distributed. When the sketch comes to Scully in a fax, she realizes that the man who burned the bar is the Marsden's driver, aka Cecil L'Ively.

Scully attemps to reach Mulder by phone, but fails. When Mulder gets to Cape Cod, he bursts into the house and finds Phoebe engaged in kissing Sir Malcolm. Annoyed, Mulder reports the suspect's name and urges gathering the family together quickly. Meanwhile, Bob the caretaker continues to watch Mrs. Marsden from a distance. By evening, Scully arrives on the Cape and reports the driver is the guilty man. Mulder says he knows, because the Marsdens' real driver has disappeared; he also found a can of fire accelerant in a tool shed. But when the Marsdens see the composite sketch of the arsonist, they say that the man isn't the driver--he's the caretaker, and he's upstairs with the children right now.

In a panic, everyone races upstairs. The Marsdens' real driver is found burned alive in the bathroom. Looking in an adjacent bedroom, Mulder finds the whole room ablaze, and realizes that L'Ively has probably rigged the entire house. Determined to conquer his fear, Mulder heads off to find the children, while everyone else heads outside. Mulder finds the children in a locked room, but then L'Ively shows up. "Time to call 911," he quips, and then sets the upstairs hallway ablaze. Leaving Mulder paralyzed, L'Ively heads downstairs, where Scully is waiting with a gun. But she cannot fire, for fear of starting a blaze and blowing the house up. Just then, Phoebe emerges from another room and douses L'Ively in fire accelerant.

Upstairs, Mulder regains momentum, gets to the Marsden children, and safely pulls them out of the house. Outside, L'Ively has burst into flames; he slowly collapses, crying, "You can't kill me! You can't fight fire with fire!" The next day, the agents return to Washington. Phoebe has gone, only leaving Mulder another cryptic tape behind; but Mulder has no interest in playing it.

Writing her case report, Scully updates on Cecil L'Ively's condition. L'Ively has been burned severely over his entire body, but miraculously seems to be regenerating. He's being kept in a hyperbaric chamber, awaiting trial for the murder of the Cape Cod caretaker; all flammable materials have been removed from L'Ively's presence because of fires that have started. In a Boston hospital, a nurse asks L'Ively if he's like anything; a charred L'Ively responds, "I'm just dying for a cigarette."

We open on Scully's apartment, where she has her parents (William and Margaret) over for dinner around Christmastime. As Scully is cleaning up, her father abruptly decides it's time to leave, and he and Scully's mom head out. Late that night, Scully falls asleep on the couch watching an infomercial on TV. She wakes to find her father sitting in the chair. Her attention is diverted when the phone rings, and when she looks back, her father is gone. When she answers the phone, it's her mother: her father has just had a massive heart attack and died.

At Jackson University in North Carolina, two college kids making out in their car are ordered out of their car by a cop. When one of the kids asks the cop for ID, he is knocked senseless. At FBI headquarters, Mulder is surprised to see Scully at work, but she insists that she is feeling OK. Mulder reviews the case of the two now-missing teens, Liz Hawley and Jim Summers; apparently, there was another, similar abduction, which occurred exactly a year ago; a week later both of the students were found dead, kept alive only for torture. Only five days now remain to find Hawley and Summers. What has Mulder intrigued is serial killer Luther Lee Boggs, imprisoned with Mulder's help years ago and set to die in the gas chamber in a week, who claims he has information about the case. He was able to describe a bracelet Hawley had in perfect detail; he claims the information came to him psychically and wants his death sentence reduced to life in prison.

Mulder believes in psychic powers, but thinks Boggs is a fraud; Boggs claims his abilities to channel came to him after the shocking experience of being strapped into the gas chamber, only to receive an executive stay. Mulder recounts Boggs' past misdeeds and concludes that Boggs is one of those people who kills just because he likes it. Boggs has requested to see Mulder, having read Mulder's profile and feeling that Mulder is the only one who understands him. Scully says she will come along, claiming she needs to work, even over Mulder's protests to take time off.

When Mulder leaves, Scully quietly pulls the X-File entitled "Visionary Encounters with the Dead," then changes her mind and shoves it back in the file cabinet. That afternoon, Scully's father's ashes are spread in a river with the song "Beyond the Sea" playing. Scully reminds her mom that her dad could have been buried in Arlington, but Mrs. Scully said this was what her husband wanted. Scully knows her parents disapproved of her decision to join the FBI, but wonders if her father was proud of her. "He was your father," answers Mrs. Scully.

Mulder and Scully travel to North Carolina and interview Boggs in prison. Boggs talks crazily, saying that demons have taken hold of his soul. He claims to be able the see the past, present, and future. Boggs, speaking in the third person, offers his life for the kidnaped kids. Checking for proof, Mulder offers Boggs a shred of cloth in an evidence bag; Boggs goes trancelike, reporting intense pain; he says the boy, Summers, is tied up with twine and is being whipped with a coat hanger. He says the kids are in a condemned warehouse and speaks of an "angel of stone" and "falling water." When Boggs finishes, Mulder tells him he ripped the cloth off of his Knicks t-shirt. Irritated and convinced Boggs is a fraud, Mulder walks out, but Scully is stopped cold when Boggs begins singing "Beyond the Sea." He asks her, "Did you get my message, Starbuck?"--using the pet name Scully's father used for her.

That night, Scully is driving around when she sees a neon display for the Hotel Niagara--"falling water"--and a statue of an angel--"angel of stone." Curious, she stops at a nearby condemned warehouse. On the ground, she finds a lit candle, a bracelet, and a coat hanger.

Scully has trouble sleeping, still seeing images of her father. Mulder turns up and says the bracelet was Hawley's. Mulder has interviewed Boggs but only got five hours of channeling. He quips, "After three hours, I asked him to summon up the soul of Jimi Hendrix and requested 'All Along the Watchtower.'" Scully then confides in Mulder that she found the scene based on Boggs' clues. Mulder is somewhat annoyed, realizing that Scully wouldn't want to go on record with a crackpot idea worthy of "Spooky" Mulder. Scully thought Mulder would be pleased that she'd accepted a paranormal idea, but Mulder can't understand why Boggs, of all people, was the turning point. Even though Mulder asks, Scully refuses to admit it has anything to do with her father. Mulder is still convinced that Boggs is working with a partner on the outside.

Mulder has a fake article planted in the newspaper, hoping that Boggs will call his accomplice to figure out what happened. When Boggs goes to make his phone call, he instead calls Mulder on his cellular and asks, "How come you don't believe me? Agent Scully does." Scully insists that it's time to deal, and Mulder reluctantly agrees. Boggs' channeling reveals a small, thin male killer in his late 20s; he also conjures up a "human skull," a boathouse on a lake, and warns Mulder "don't go near the white cross." Boggs' channeling is intercut with the kidnaper beating the kids in exactly the manner Boggs describes.

The FBI descends on the boathouse and finds Liz Hawley inside. While sweeping the docks, Mulder is shot by the kidnaper. Scully rushes to his side, and looks up in horror to see the masts of an old sail forming a white cross. Mulder and Liz Hawley are both taken to the hospital for treatment. When she regains consciousness in the morning, Hawley fingers the kidnaper as Lucas Jackson Henry, who fits Boggs' description perfectly. In younger days, Henry's girlfriend and mother were both killed in a car wreck--seven years ago to the day from the date of the previous killings. Local police believe that Boggs had an accomplice on his last five murders; Henry was suspected but never proved guilty.

Scully angrily goes to Boggs' cell and screams at him for setting Mulder up and says that she will personally throw the switch to kill Boggs if Mulder dies. Boggs begins channeling again, over Scully's protests that she doesn't believe him. But this time, Boggs channels Scully and recounts an incident from her childhood which she never told anyone, involving sneaking out with her mom's cigarettes. Still doubtful but beginning to cry, Scully says she will believe Boggs if he will let her speak to her father. Boggs begins to channel, but then interrupts and refuses to speak until he gets a deal. He says the last time he went to the gas chamber, he began to see the faces of all the people that he had killed; he said he was suddenly infused with the fear of all his victims, and other souls rushed into his body. Scully says she doesn't believe, but Boggs calls her out as a liar, and a visibly shaken Scully leaves him.

Scully meets with the governor of North Carolina, but he refuses to stay Boggs' execution. She then goes to see Mulder in the hospital and brings him up to speed on the case; Mulder insists that Scully should not believe and that the whole case was a set-up to get even with Mulder. He is concerned that Boggs may be trying to claim Scully as a final victim. Scully meets with Boggs again and tells him that she's made a deal. Boggs channels again, saying he sees "vats," and the Blue Devil Brewery, and the boy about to die. Scully is about to give up Boggs as a fraud until he tells Scully he knew she was lying abou the deal--but that she tried. In his parting words, Boggs says, "Avoid the devil. Don't follow him to the devil. Leave that to me."

Scully and other FBI agents descend on the Blue Devil Brewery, and everything is as Boggs said it would be. They are just in time to stop Jim Summers from being killed. Henry runs, and the agents give chase. Henry charges out onto a rickety catwalk; Scully is about to pursue, but she sees a Blue Devil logo on the wall, and remembering Boggs' warning, holds back. The catwalk collapses, and Henry plunges to his death.

Scully visits Boggs in his cell; she believes him, knowing that if he was orchestrating the kidnaping, he never would have sent Henry across the catwalk, nor warned Scully about it. Boggs tells Scully if she wants a final message from her father, she has to come and be a witness to Boggs' execution. Boggs is brought his last meal, walks down death row, and is strapped into the gas chamber. But as the gas begins to do its work and the witness curtain is drawn back, Scully isn't there.

Instead, Scully has returned to Mulder's bedside, where she tries to rationalize all that Boggs did: she speculates that if he knew that she was Mulder's partner, he could have found out everything about her. But now Mulder has turned the tables: he wonders why, after all she's been through, she cannot believe. The truth finally comes out of Scully: "I'm afraid to believe." Mulder questions the price--not being able to hear her father's final message--but Scully says she knows. When asked how she knows, she just replies, "He was my father."

The episode begins in the air over Iraq, when an Iraqi pilot notes a strange object buzzing around the sky; it is invisible to ground radar. As quickly as it appears, it vanishes. Suddenly, the pilot's cockpit is filled with bright white light. He locks a missile onto the object and fires. He scores a hit, and the craft crashes down near a NATO surveillance station in Turkey. The soldiers at the station go to check out the crash, even though it was not picked up on radar.

We cut to Reagan, TN, where a trucker named Ranheim is making his way across the country in a tractor trailer. Suddenly, his radio goes crazy, scrambling over all the stations; on the CB radio, he hears other truckers mentioning cops converging on a UFO sighting. Ranheim's truck then loses all power and comes to a stop. He goes to check out his cargo, with shotgun in hand, noting a weird UFO in the sky. He fires several shots into the back of his truck.

Mulder and Scully are on the scene the next day. Mulder immediately suspects UFOs, but Scully tries to come up with more rational explanations, such as weather disturbances; the trucker probably fired on a wild animal which had come too close to his truck. She also thinks the lights people saw in the sky may have been ignited swamp gas. Mulder is not so sure that dozens of people and cops across three counties would have been alarmed by swamp gas. Meanwhile, he starts two stopwatches, leaving one by his car and carrying another along. Using a Geiger counter, he finds a pile of radioactive material and collects a sample. When he gets back to the car, the stopwatches show different times.

Under questioning by the agents, Ranheim can't recall whether the UFO was cigar-shaped and black or saucer-like with lights. Ranheim mentions that he's a veteran, and Scully notices that he exhibits all the symptoms of Gulf War syndrone; Ranheim mantains, however, that he was never in the Gulf War. When asked how long he "hasn't been himself" by Mulder, Ranheim answers since his encounter with the UFO. Their questioning is interrupted by the local sheriff, who releases Ranheim and says that the county will no longer cooperate with Mulder's investigation. Forced to leave, Mulder and Scully go to return their rental car; while waiting, Mulder expresses his feeling that someone "got to" the chief and made him shut up. He also thinks that Ranheim is hiding something, possibly connected to his illness. Scully thinks Mulder is trying to blame Gulf War syndrome on UFOs, which he admits is a possibility; Scully suggests that most UFOs seen by soldiers are just secret aircraft.

Returning to Washington, Mulder goes to meet with three friends (the Lone Gunmen) who are conspiracy theorists: Frohike (a squad guy always seen in vests), Byers (a dapper professor-type in a brown suit), and Langly (a rebel with long blond hair). While there, they bounce a few new theories off of Mulder: Langly says he had breakfast with the guy who shot JFK, Byers thinks Russian leaders are being put into power by the CIA, and Frohike has just analyzed Scully and concludes, "She's hot." When Scully shoots down Byers' theory, Frohike further comments, "Wow. She's really hot." Byers then defaces a 20-dollar bill provided by Scully, explaining that the anti-counterfeiting strip is really a tracking device. When Mulder tries to bounce his UFO/Gulf War syndrome theory off the gunmen, Byers replies, "That's why we like you, Mulder. Your ideas are weirder than ours."

Back at the X-Files office, Scully comments on how deep the paranoia of the Gunmen runs--right up until she goes to change the ink cartridge in her pen and spots a tracking device inside it. She realizes that a woman she ran into at the car rental agency must have swapped pens with her. Mulder returns to his apartment and swaps a blue light bulb into the lamp by his window to contact Deep Throat. Hours later, Mulder gets the customary clicking phone call and meets Deep Throat at a park bench on the waterfront in Washington. When Mulder asks what he's on to, Deep Throat just tells him he's on a dangerous path and hands him a folder full of information.

Contained in the package, Mulder finds a complete radio transcript of the UFO shot down over Iraq. While Mulder is reading, Scully comes into the office and tells him that Ranheim and his cargo were bogus. Comparing his manifest to the results of the truck in weigh stations, the truck is 2000 pounds lighter than it should have been--indicating additional cargo. With additional digging, she also learned that Ranheim's real name is Frank Druce, and he was in the Black Berets running special operations in northern Iraq during the Gulf War. Mulder thinks that Druce picked up the UFO and any survivors and is driving the cargo to a lab somewhere in the US. Scully has only been able to learn that the truck is heading west toward Colorado.

Mulder returns to his apartment to find his power cut and Deep Throat waiting for him with vital information. He provides Mulder with UFO pictures taken recently over Fort Benning, GA, indicating that this may be were the Iraqi wreckage wound up. Mulder shows Scully the photo, excited at the new evidence, but Scully is able to quickly find evidence that the photo is a fake. Unwilling to believe, Mulder heads out, barely heeding Scully's advice that despite her admiration for his passion, others may use it against him.

When Scully heads into the office the next morning, she is surprised to find Mulder there. He had the photo analyzed by the FBI's computers, and closer examination proved that it was a fake; Mulder realizes Deep Throat has finally lied to him and sent him on the wrong track. Mulder meets with Deep Throat in an aquarium and demands to know why he was lied to. Deep Throat is impressed with Mulder's detection of the deception. He says that he has been watching Mulder for some time and realized he was the right vehicle for bringing the government's deepest secrets to light. Nonetheless, he maintains that some things must remain secret--hence the fake photo. Mulder criticizes Deep Throat, saying that no one has a right to determine what the truth is. Deep Throat parts by telling Mulder that he and Scully are still under surveillance.

Mulder returns home and rips his apartment apart searching for a bug; he finally turns one up inside one of his electrical outlets. Scully shows up to talk to Mulder; he keeps the conversation light, saying they should drop the case, while he points the bug out to Scully. He writes her a note saying they need to find the truck. The agents drive out, split up, fly to several different locations, and then meet up again in Las Vegas, having taken great effort to shake the people tailing them. Scully has, in the intervening time, tracked down the truck and knows it's heading toward Seattle, WA.

The agents stake out a highway junction, wait for the truck to pass, and then go chasing after it. The chase goes on for several hours and winds up in some very remote country. Scully thinks that the driver may be on to them and is taking an evasive route. Suddenly, their radio goes crazy and there is a bright white flash of light ahead. Scully stomps on the brakes, and they find themselves right next to the truck, which has skidded to a stop. Ranheim has disappeared from the truck. Mulder looks in the cargo, and moving several boxes out of the way, finds a miniature medical lab in the back, complete with a table and straps. Mulder is convinced the government picked up a live extraterrestrial biological entity (E.B.E.); he thinks they just witnessed an alien rescue. However, when he checks the scene with his Geiger counter and the stopwatches, it appears to be another hoax. He suspects the government played on his belief in alien life and thought he would just accept the obvious and walk away.

Checking into a hotel, Mulder calls several UFO watch groups and gets a listing of major sightings. All of the sightings coincide remarkably with the route of the truck, all the way from Tennessee. The trail ends in a mass of sightings in Washington, about 100 miles from their present location. The agents drive around most of the night until they happen upon a group of wackos having a UFO party. One of the people at the party points Mulder to a power plant just a few miles away.

Mulder and Scully put the place under surveillance, and when they see Ranheim walking out through the high security, they know they've found the right place. Mulder calls the Lone Gunmen and offers them exclusive EBE photos provided they can hack two security clearances for Mulder and Scully, which Langly is more than happy to do. With their fake IDs, Mulder and Scully sneak their way into the base and try to find the one room that their badges won't give them access to. They find the room, but are immediately fingered by a security guard. Scully gives up the charade, but Mulder busts into the high security room at a sprint. He finds inside a strange looking lab and a bed. He charges toward it, but is stopped by guards with machine guns, just inches shy of seeing what's in the bed.

The situation is immediately defused by the arrival of Deep Throat, who calls the guards off of Mulder. He refuses to show Mulder what's in the bed, but assures him it's dead. He also says that most of the major world powers had a secret meeting after the Roswell incident in 1947 in which they agreed to exterminate any E.B.E. they captured. Deep Throat claims he's one of only three men to have ever killed an E.B.E.; he says he was in the CIA in Vietnam when the incident occurred. His guilty conscience has haunted him ever since; he comes to Mulder to atone for his sins. Unable to resist any longer, Mulder goes to look at the bed and finds it empty.

Leaving the building, Mulder comments to Deep Throat, "I'm wondering which lie to believe." Deep Throat only chuckles and walks away.

In the Olympic National Forest in Washington state, a group of loggers is having an argument. They are concerned about something in the forest coming to kill them; in the end, they decide to split up and make a run for civilization as quick as they can. Night falls quickly on the running men. One falls and twists his ankle, and another tries to hoist him up. Suddenly, the air is filled with a strange buzzing, and a swarm of green insects descends upon them. Both the men scream in terror.

Mulder and Scully come onto the case when the Federal Forest Service reports that all 30 loggers from the site have disappeared without a trace. The logging company with the clear-cutting contract reports the presence of an eco-terrorist named Doug Spinney in the area causing trouble; two forest service people were sent in to figure out what had happened, and they were lost as well. What has Mulder intrigued is that a WPA logging crew vanished under similar circumstances in the same area in 1934--clearly not the work of eco-terrorists. "Come on, Scully," says Mulder, "it'll be a nice trip to the forest."

The agents fly out to Washington and meet up with Larry Moore, an officer with the forest service who will be driving them into the woods. He makes clear that he agrees with the eco-terrorists in principle, but not in method; he also knows that something very serious must have happened to kill off 30 loggers, all of whom had survival training. Also joining the party is Steve Humphreys, head of security for the lumber company.

The drive out to the site takes four hours over rough roads. Along the way, Humphreys explains that the site is so remote because the eco-terrorists and their ilk have made sure that most of the forest land in the area is protected. Just then, the truck the group is driving in blows a tire; Moore finds a spike embedded in the rubber--the work of eco-terrorists. With no spare tire, the group is forced to hike the rest of the way to the logging camp.

Mulder and Scully and the others arrive to find the camp deserted--and deserted in a hurry, gear unpacked and food left on the table. All the vehicles have been disabled (radiators full of rice, gas tanks full of sugar), the power generator is broken, and the radio is smashed. Looking around the area, Mulder spots a bizarre cocoon in one of the trees. Using a block and tackle, Scully is hauled up to cut the cocoon down. When she opens it up, a shriveled and dessicated human corpse is found inside. Scully wonders what insect could have hauled a man up into a tree.

Elsewhere, Humphreys is working to get the camp generator working when he spots someone rooting through the cabin; he busts inside and holds the infamous Doug Spinney at gunpoint. Humphreys demands answers; Mulder arrives and gets Humphreys to put his shotgun down. Spinney says that darkness is the enemy and that they'll all be dead without the generator working. He says that "something" comes from the sky, picks up men, and devours them whole. Humphreys doesn't buy the story, but the cocoon makes the others curious.

Spinney says it's impossible to hike out, since it's more than a day's walk; he has to go back to his camp two valleys away and bring a jeep back. Humphreys wants Spinney, an admitted felon, arrested. Spinney insists he and his now-dead friend were just "camping" and that he has spotted the loggers cutting down trees that are protected from logging. He says that their only chance for survival through the night is to stay in the light, which the creatures are afraid of. Not buying the story, Humphreys goes outside to prove that Spinney is a liar. Nothing goes after Humphreys, but on the shadowed side of a tree, strange glowing green bugs are visible. Not taking chances, Mulder decides to keep the lights on.

The following morning, Spinney shows the group a marked (and therefore protected) tree that the loggers felled; Humphreys suspects that Spinney marked the tree himself to cause trouble. Looking at the rings of the fallen tree, Mulder notes that there's a bizarre black ring several hundred years in. Humphreys insists on arresting Spinney, but none of the agents are willing to; Humphreys is intent on getting answers back to the families of the loggers, and he thinks that looking at old, dead trees is a waste of time. Later, Moore examines a core sample he took from the old tree and is surprised to find some kind of tiny insect living in the wood, feeding off of the dead wood; Mulder wonders if the insects have been in the trees for hundreds of years. Spinney notes that the problems started developing shortly after the tree was cut down; he thinks the bugs have been dormant and "woke up hungry."

Humphreys spends the rest of the day and into the night trying to fix one of the camp's trucks so he can use its radio. In the evening, he hears a noise in the treeline; suspecting eco-terrorists, he goes to investigate. Instead, he is swarmed by tiny green insects while still working to start one of the trucks. Back at the logging cabin, the others have begun to wonder where Humphreys is. Scully has noticed that the bugs have either died or become inactive in the light, and Mulder notices that all the surfaces in the cabin are covered with a thin slimy film. Mulder thinks that a volcanic eruption hundreds of years ago and the subsequent radiation release gave rise to mutated insects; otherwise, it may be an extinct species that was trapped in the tree by an eruption, laying dormant until the tree was cut down.

Early the next morning, Spinney rises before the others and takes most of the remaining gasoline. He is intercepted by Mulder, but explains he's going back to his camp to get a jeep; he also says he has to get his friends out before they run out of gas for their generator. Mulder decides to trust Spinney and let him go. Later, Mulder gets the radio working, only to have Moore shut off the generator to conserve gas; both Scully and Moore are irritated that Mulder allowed Spinney to leave. Stuck with the decision, Mulder decides to button the cabin up as tightly as possible to try and keep the bugs out.

That night, no one is able to sleep; they can only watch the solitary light bulb in the cabin flicker as the gas in the generator runs lower and lower. Looking in a dark corner of the room, Scully notes a large number of the insects crawling in. When she sticks her hand into the dark, she sees them crawling all over her skin and freaks out. Mulder calms her and says he thinks the bugs are the greasy residue on everything; he suspects that the light is what keeps the bugs from swarming. Scully realizes that Mulder's call for help didn't get through, but Mulder has faith that Spinney will return.

The generator gives out, but just as the sun peeks over the horizon. During the day, Mulder, Scully, and Moore work to repair their truck's flat tire; when they reach the vehicle, they find Humphreys' cocooned body inside. Just then, they hear the sound of a car; Spinney has kept his word and returned with his jeep. All of Spinney's friends are dead; everyone piles into the jeep and Spinney takes off for civilization. Just as darkness falls, the jeep runs over some spikes and gets a flat--Spinney has fallen victim to his own trap. Insects swarm the group and everyone is cocooned.

Fortunately, Spinney radioed for help and a rescue team arrives shortly thereafter. Mulder, Scully, and Moore are severely weakened but alive--Spinney is killed. They are placed in quarantine for a month. One of the technicians tells Mulder that their bodies were covered with the enzyme that causes fireflies to glow. Mulder looks at the weakened Scully and can only say, "I told her it was going to be a nice trip to the forest."

Mulder wonders how the insects will be contained, and the tech says that controlled burns and pesticides should do the job. Mulder then questions what will happen if the control isn't successful. The tech answers, "That is not an option, Mr. Mulder."

The episode opens with a high-speed police chase, a solitary man driving away from two cops. The man is ultimately cornered by additional patrol cars in a ship dock. Exhibiting great strength, the man breaks free of the cops, and seems unaffected by a taser shot to his chest. Despite also being shot several times, the man continues running and dives off a pier into the water, bleeding a green residue.

Story note: During the credits, the closing tag line reads "Trust No One" instead of "The Truth Is Out There." This is the first time in history the tag line was changed.

Mulder is at home sleeping on his couch on a Sunday when he gets a call from Deep Throat, telling him to change channels. He flips to a news broadcast (which he records), detailing the car chase leading up to the man jumping off of the pier. Mulder calls Scully in, but after watching the tape several times, he cannot glean what Deep Throat wants him to find.

The agents head down to the boat docks; the officer in charge says he cannot recognize one of the men in a still picture of the videos that Mulder shows him, but also says that three law enforcement agencies were crawling all over the scene. Mulder is also suspicious because the man was shot, yet no body has been found by divers yet. Mulder asks to see the suspect's car, and the police captain says it's been impounded. The agents head to the impound lot and go over the car in detail, but can find nothing of significance--until Mulder compares to a picture from the video and notices a sticker missing from the windshield, indicating the cars are not the same. The symbol is the two snakes intertwined on a staff--the classic symbol of the medical profession, indicating the car belongs to a doctor. By having the video enhanced, Mulder gets a partial license plate reading and has it traced

The agents head to the Emgen Corporation in Gaithersburg, MD, to speak with a Dr. Berube, the traced owner of the car. Berube does experiments on monkeys and chimps; he is short with the agents, unwilling to talk about his work or the missing car. He says his housekeeper sometimes takes the car, which is why he didn't notice it was missing. Scully is ready to drop the case, tired of chasing Deep Throat's thin lead; she's sick of him "rationing out the facts." "What, you think he does this because he gets off on it?" asks Mulder. "No," says Scully. "I think he does it because you do."

Mulder returns home, where he is met outside by Deep Throat. Deep Throat is disappointed that Mulder's enthusiasm for the case has diminished, but Mulder says that he's fed up with following thin leads and playing the game on Deep Throat's terms--he has enough other work to do. Nonetheless, Deep Throat encourages Mulder not to give up, saying that "you've never been closer"--though he won't say to what. That evening, Dr. Berube is met by a shadowy man, who wants to know if "he" is alive and has been in cotact; he also wishes to know where a Dr. Secare is. The man assaults and then murders Berube. Back at the docks, the police haven't found a body and decide to give up. Just as they leave, the supposedly dead man emerges from the water, very much alive.

Mulder and Scully's trail becomes hot again when Berube is found dead. The police suspect a suicide (Berube tied gauze around his neck, the other end around a pipe, and then jumped out a window), but Mulder can't understand why the immaculately clean Berube would trash his own lab. Background work reveals that Berube was working on the Human Genome Project. Looking around, Mulder turns up an Erlenmeyer flask labeled with the words "Purity Control"; Scully doesn't know what it is, but says she will try to find out while Mulder goes fact-hunting for more on Berube. Mulder goes to Berube's house, and finding it empty, slips himself into the house through an open window.

Meanwhile, Scully consults with a Dr. Carpenter at the Georgetown Unversity microbiology lab to determine what's in the flask. Carpenter's analysis turns up a very bizarre form of bacteria. Scully decides to wait around while more tests are done. Back at Berube's house, Mulder looks through some phone records and finds a number that Berube dialed dozens of times; he calls the FBI to have the number traced. While he's waiting to be called back, someone calls Berube, and it turns out to be the injured man who jumped off the dock. He's calling from a pay phone, but he collapses in pain and a bystander hangs the phone up before Mulder can get the location. Mulder then gets his callback from the FBI; the number traces to a company called Zeus Storage. As he's finishing his call, Mulder looks outside and sees a van pulling away, where someone has been monitoring his actions the entire time.

Meanwhile, the mystery man oozing the green blood is being hauled away by paramedics. They insert a needle into his chest to relieve pressure, but when they do, a gas oozes out of him and the paramedics are overwhelmed by the gas. The ambulance swerves off the road, and the mystery man escapes. Mulder calls Scully and tells her that the fugitive is still alive. Meanwhile, Scully has turned up some bizarre things with the bacteria: it contains chloroplasts, which are ordinarily only in plant cells, and is also stuffed full of a virus, which is only done to perform gene therapy on higher animals. She says that the discovery is highly significant; bacteria like this haven't existed for millions of years.

Mulder drives up to Zeus Storage to have a look around. Using Dr. Berube's keys, he admits himself to a strange storage room, where human bodies, still alive, are suspended in tanks of fluid. Time elapses, and early the next morning, Dr. Carpenter presents Scully with a bizarre DNA analysis of the bacteria. It seems that the bacteria's DNA has "gaps" in the sequence because it posesses an additional set of base pairs never before seen in nature. She says that the bacteria must be extraterrestrial in origin. Back at Zeus Storage, Mulder leaves only to be briefly chased by some strange men, but they quickly give up on him.

Mulder returns home just in time to catch a phone call from Scully, who fills him in on the strange bacteria. The two then travel to Zeus Storage so that Mulder can show Scully what he's found. On the way in, Scully apologizes to Mulder for suggesting they terminate the case; she says that she always placed her faith in science, but now science has shown her something unbelievable. Mulder says, "When you walk into that room, nothing sacred will hold." Unfortunately, when they arrive, everything that Mulder saw has been removed.

Just as Scully is asking where the bodies may have gone, Deep Throat walks in and says they've probably been destroyed, though he doesn't know by whom. Mulder finally starts to put the pieces together: Dr. Berube was conducting experiments on human subjects using extraterrestrial viruses. Deep Throat says that's only part of the story, and has been going on since the Roswell crash in 1947. Berube was apparently killed because his work was too successful. He successfully created alien-human hybrids, using terminally ill volunteers as subjects, including his friend, Dr. Secare--who is now the fugitive. Deep Throat says that Secare's cancer disappeared and he developed incredible strength and the ability to breathe underwater, which allowed him to elude divers searching for his body. But Secare was never expected to survive, and the secrecy of the project precluded the possibility of a hybrid with toxic blood chemistry running around in the general population. Deep Throat is only giving the agents all this information now because the clean-up is proceeding much faster than he expected; he says they have to get to Secare before the government goons do.

Scully heads back to Georgetown, and Mulder goes off to find Secare. But when Scully reaches Georgetown, she is shocked to learn that her collaborator, Dr. Carpenter, was just killed in a car accident, along with her entire family. Mulder returns to Berube's house to hunt for clues, but it turns out that someone is there, hiding in the attic, when he arrives. Mulder heads into the attic, thinking that Secare might be hiding out there. Secare jumps him, but calms himself when Mulder offers protection. Before Secare can reply, another man pops up into the attic (with a gas mask on) and shoots Secare. Mulder gets a whiff of Secare's green blood and collapses, clawing his eyes in pain. Secare's body is taken away, and Mulder is taken into custody.

Early the next morning, Scully goes to Mulder's apartment looking for him, but she runs into Deep Throat, who says he isn't there; he does assure her that "they" won't kill Mulder. Deep Throat says evidence is still available--the original alien tissue, being held at the High Containment Facility in Fort Marlene, MD. If Scully can get the tissue, they may be able to swap it in exchange for Mulder. Deep Throat forges Scully an ID badge, and Scully finds her way into the facility, using the project password "Purity Control." There, in cryo-freeze, she finds and takes what appears to be an alien embryo.

Scully and Deep Throat arrange to make an exchange for Mulder on a bridge outside Washington, D.C.. Scully wants to pass the embryo, but Deep Throat is insistent on making the exchange himself; he made the deal, and his counterparts are expecting him. He points to a case where several children were injected with DNA from the clone in 1987 as a test, and their parents were told it was a routine vaccination--"that's the kind of people you're dealing with," says Deep Throat. He insists that Mulder's life is worth the risk, because he and Scully are the only ones who can expose the conspiracy. Scully relents, and Deep Throat makes the exchange. Just as Mulder is dumped out onto the street, groggy but alive, Deep Throat is gunned down. Seeing that Muder is alright, Scully runs to Deep Throat, who manages to breathe out the words, "Trust no one" before he dies.

Days pass, and late one evening, Scully gets a phone call from Mulder. The X-Files are being shut down, and Mulder and Scully are going to be reassigned. But Mulder says that he will never give up, "not as long as the truth is out there." Across town, the Cigarette Smoking Man takes the recovered alien embryo into the basement of the Pentagon and stores it away where it will never be found.