The Earth is invaded by hordes of monstrous Spidercrabs under the control of the Venomoid warlord, DARKON. His first target is the Space-Ring, a huge orbital space station surrounding the Earth. Suddenly, an armored figure appears -- the Teknoman, SLADE -- who attempts to stop the attack, but is confronted by GUNNAR, one of the mutant Teknomen under Darkon's control. In the ensuing battle, Slade is badly wounded and sent plummeting toward the planet below, where his explosive impact creates a gigantic crater. The SPACE KNIGHTS, RINGO and STAR, are sent to investigate and are amazed when the injured Slade emerges from the crater. They take him back to their base and nurse him back to health. They have no clue as to Slade's identity or where he came from, and neither does Slade, who can remember only two things: his name is Slade and he must stop the aliens from conquering Earth.
The "Blue Earth" is damaged and is forced to make an emergency landing on the Space-Ring. RINGO questions SLADE about his ability to transform, but Slade claims he still can't remember anything. Ringo suspects Slade is hiding something and is determined to find out what.
In an attempt to place SLADE under his command, GENERAL GALT orders an armed take-over of the Space Knight Command Center. But his plan is foiled by the intervention of the PRESIDENT OF THE TERRAN PLANETARY COUNCIL. Meanwhile, a section of the Space-Ring has become detached from the station and is falling toward Earth.
The SPACE KNIGHTS are sent into action against the aliens. The mission is a success, but SLADE'S energy is almost totally depleted and he is left drifting helplessly in space. RINGO thinks that he and STAR should head for Earth while they still can, but Star insists that they go back and save Slade.
SLADE tells TINA he now realizes that if he remains in his TEKNOMAN guise for longer than thirty minutes, the Teknoman side of his being will take over. He will lose his "soul" and become a slave of the VENOMOID WARLORD DARKON. He makes Tina promise to have RINGO blast him out of the sky before that can happen.
The SPACE KNIGHTS receive a distress call from the Space-Ring, supposedly from survivors of the previous attack. SLADE and the Space Knights are sent to rescue them, but it turns out there are no survivors.
MAGGIE attempts to design a TEKNOBOT which, when SLADE enters its Interlock Chamber, will amplify the power of his shattered Tekno-crystal and enable him to transform into TEKNOMAN again. Meanwhile, GUNNAR announces that he will call off the attacking SPIDERCRABS if Slade is handed over to him. Slade steals a rocket and flies off to meet Gunnar one-on-one, carrying a bomb he believes will blow Gunnar (and himself) to atoms.
GENERAL GALT, anxious to know the source of Tekno-power, sends BALZAC to infiltrate the SPACE KNIGHTS in the guise of a war correspondent. Meanwhile, the aliens are attacking Earth with the computer controlled Space-Ring laser cannon. COMMANDER JAMISON tells the Space Knights that they must alter the computer's laser-control program without attempting to destroy the computer. If the computer is damaged or destroyed, its back-up system will switch on all the lasers and the Earth will be destroyed. Balzac accompanies the Space Knights on their mission. After boarding the Space-Ring, a fight between the aliens and TEKNOMAN sets off the back-up system, and Balzac is the only one who can figure out how to disable the system.
One of JAMISON'S old friends, DR. SILAS RANDOM, a long time opponent of the military's efforts to take control of the planetary government, is in command of an Earth-bound convoy carrying vital supplies. Random transmits several messages over an "open" channel (one that can be picked up by VENOMOIDS), leading the SPACE KNIGHTS to believe that he's planning to lead the convoy into a trap.
SLADE, STAR and RINGO are assigned to help a Special Forces Commando Squad retrieve three ultra-speed attack fighters from the Space-Ring. When the "Blue Earth" is damaged by SPIDERCRABS, Ringo and Star are forced to return to Earth. Slade fights his way to the Space-Ring where he meets CAPTAIN MILES O'ROURKE, leader of the Commando Squad. O'Rourke resents an outsider interfering with his mission, just as Slade resents having to assist in a military operation. But as they fight their way toward a common objective, a mutual respect develops between the two. Later, when Slade congratulates O'Rourke on the "success" of the mission, the Commando leader reminds Slade that during the so-called "success," they lost three men and asks, "How do you think the families of those three will feel when they hear of their loss? War isn't numbers, Slade, it's people. Never forget that."
During a combined SPACE KNIGHT/military attack against the SPIDERCRABS infesting the Space-Ring, a young cadet is partnered with a seasoned veteran who teaches him about the glories and horrors Episodic of war. After the battle, SLADE gets an unpleasant surprise!
When the SPACE KNIGHTS are given shore leave, TINA, MAGGIE and STAR go to the shopping mall. When they see SLADE there, they call out to him but he doesn't respond to their greeting. Later on, they learn Slade wasn't at the mall. In fact he's been with MAC at the Command Center all day. The women are amazed, saying, "This guy could have been Slade's twin!" Slade immediately knows what this means -- his twin brother SABER, one of DARKON'S most lethal warriors, has come looking for him. Shortly thereafter, the twins meet and Saber mocks Slade for being weak, for refusing to acknowledge the dark side of his Tekno-nature and rejecting the gift of unlimited power Darkon has offered them. The twin brothers fight, and Saber gains the upper hand just as Slade's thirty minute time limit is about to expire.
The VENOMOIDS attack a nuclear fusion plant in order to steal the Earth's energy. When SLADE rushes to oppose them, SABER appears and the two TEKNOMEN do battle once again. During the fight, more images from Slade's childhood flash through his mind. He sees himself and Saber playing as brothers with their sister, SHARA.
SLADE has been in his Tekno-mode too long and he can't change back. He sinks deeper and deeper into the dark side of the TEKNOMAN person. In an attempt to get him to transform back to his "human" self, TINA, who reminds Slade of his sister SHARA, risks her life by confronting the inhuman monster which Slade has become.
BALZAC discovers COMMANDER JAMISON'S secret underground research laboratory below the Command Center. While the SPACE KNIGHTS are responding to an alien attack, Balzac bypasses Jamison's security system and enters the lab. To his surprise, Balzac finds Jamison, who's known his true identity all along, waiting for him. Balzac's surprise increases when Jamison gives him the information he's been sent to find. A complete record of all research concerning Tekno-power and its potential use in the creation of a Tekno-suit.
GENERAL GALT orders COMMANDER JAMISON'S SPACE KNIGHTS to protect a facility that produces Zeetron, a substance essential to the production of the military's Tekno-suits. A huge squadron of aliens attack the facility and SLADE, afraid that he will lose control again and hurt his friends, is reluctant to transform into TEKNOMAN. STAR finally convinces Slade to transform and he, as Teknoman, goes to defend the facility. But his help turns out to be unnecessary.
The new "TEKNOMAN" turns out to be BALZAC, wearing the military's newly developed Tekno-suit. Meanwhile, Balzac's friend MARLOW, the scientist responsible for designing the Tekno-suit, is hurt while attempting to transport the suit's Zeetron power source to a safe location. Balzac blames SLADE for Marlow's injuries and accuses him of cowardice because Slade delayed his transformation.
Shell-shocked, SLADE has been put in the "care" of GENERAL GALT, who is studying him in an effort to improve the design of the military's Tekno-suit. STAR and RINGO break into Galt's headquarters to try and free Slade so he can help against the VENOMOIDS.
Despite the aliens' furious attack against the Allied Military Command's headquarters, SLADE refuses to transform himself into TEKNOMAN. He fears the VENOMOID monster he will become if he exceeds the thirty minute limit. Frustrated by Slade's reluctance, RINGO takes matters into his own hands by hijacking Tekno-suit Number Two and going out to meet the enemy.
It's obvious to RINGO that SLADE and STAR'S mutual shyness is preventing them from developing the romantic relationship they both want. During a racquetball game, Ringo gives Slade some "man-to-man" advice about how to resolve the situation. Meanwhile, Slade's sister SHARA leaves DARKON'S base on the moon to search for Slade and to warn him about Darkon's plans.
Arriving on Earth, SHARA finds herself in a desert village where she transforms into her TEKNOWOMAN person to save a little girl from a SPIDERCRAB. Meanwhile, JAMISON rushes to develop a new and devastating weapon with which SLADE can defeat SABER -- an anti-matter warhead missile.
SABER, leading an attack which has almost destroyed the Space Knights' Command Center, demands that SLADE come out and fight him. RINGO buys some time for Slade and the Command Center by attacking Saber in Tekno-suit Number Two.
SLADE tells the SPACE KNIGHTS the story of how he became involved with the VENOMOIDS. His real name is NESS CARTER and his family was aboard the deep-space research vessel "Argos" when it encountered a strange alien craft near the rings of Saturn. Thrilled at the prospect of an encounter with extra-terrestrials, they boarded the vessel, only to be attacked by frightening creatures called TEKNOPODS, which like the Terran plant called the Venus Fly Trap, swallowed them whole.
SHARA warns SLADE about DARKON'S secret underground base on the dark side of the moon. She also warns him about the imminent arrival of three more evil TEKNOMEN - LANCE, AXE and SWORD - who are being sent by Darkon to help Saber destroy Slade.
Mistakenly believing that the aliens are using the Space-Ring as their headquarters, GENERAL GALT launches an Ultron Bomb to destroy it, in spite of the millions of human lives which will be endangered by the resulting debris falling to Earth. SLADE succeeds in destroying the bomb. Meanwhile, an ailing SHARA leaves the Command Center in order to help Slade by destroying SABER and his TEKNOMEN cohorts.
This is a recap of the series up to this point, told from Star's point-of-view. An unidentifiable, hooded figure picks up an audio-computer chip from the deserted area near the demolished Space Knight Command Center. When the hooded figure opens the chip's casing, the voice of COMMANDER JAMISON narrates the story of "The efforts of the SPACE KNIGHTS on behalf of the planet Earth, including those of NESS CARTER, better known as the TEKNOMAN, SLADE."
In a Middle Eastern village, a young boy named RASHID mistakes RINGO (in his Tekno-suit) for the mythical RED SAVIOR. According to legend, the Red Savior will protect the residents from the alien invaders. When AXE and the other evil TEKNOMEN show up, Ringo's best just isn't enough.
Just as the batteries of the "Green Earth" (The SPACE KNIGHTS' surface vehicle) are in need of recharging, the group finds a town that has a generator. Fearing that use of the generator will result in discovery by the VENOMOIDS, the townspeople refuse to help the Space Knights. In spite of the town's precautions, the Venomoids attack.
RINGO goes home and discovers that his mother and father are casualties of the war with the aliens. He also finds out that his hometown has been devastated by a gang of roving outlaws known as the HYENAS, who prove to be no match for the SPACE KNIGHTS. Ringo donates is family estate as a playground for the local school children. As they continue on their journey, SLADE and the other Space Knights decide the only way to reach DARKON'S moon base is to sucker AXE into a trap and to take his Tekno-crystal. They find a town which is brightly lit, a sure invitation for a SPIDERCRAB attack. It turns out that the town's inhabitants are members of a Special Forces Mortar Squad who are trying to lure the aliens into a trap, which seems to fit in perfectly with the plans of the Space Knights. Axe takes the bait and, along with a squadron of Spidercrabs, attacks the town.
The "Green Earth" comes upon a mysterious castle where they are greeted by a robot named TORG, the servant and companion of GLORIA, the mistress of the castle. In complete denial about the alien invasion, Gloria claims to be awaiting the return of her grandfather, who left the castle six months earlier. RINGO, however, discovers that Gloria's grandfather passed away a year before the invasion, which means that Gloria is living in a fantasy world, out of touch with reality. When the aliens attack the castle, the SPACE KNIGHTS try to convince Gloria to leave with them, but she insists on remaining in the crumbling castle.
After SLADE and RINGO rescue a woman, RACHEL, from an alien attack, she invites the SPACE KNIGHTS to spend some time at her farm. There they discover that the man living with her is none other than BALZAC, GENERAL GALT'S spy, for whom they bear little affection. But Balzac, it turns out, is a changed man.
SLADE, knowing that he walking into a trap, answers AXE'S telepathic Tekno-summons and goes to meet him in combat. The other SPACE KNIGHTS are prevented from joining Slade in his fight with Axe, and watch helplessly as Slade fights what appears to be a losing battle.
SLADE is fighting AXE, who used to be GRANT GODDARD (Slade's karate instructor and one of the crewmen aboard the "Argos") before being transformed into a mutant Teknoman. Axe encases both of them in a web of impenetrable thorns, where he intends to fight Slade to the end.
Near Iceland, BALZAC and RINGO have to cut through the ice and go underwater in order to retrieve a micro-chip needed by COMMANDER JAMISON at the new Command Center in Alaska. When they're attacked by aliens, SLADE is about to go and help them when SGT. O'ROURKE orders him not to! O'Rourke then explains that, according to Jamison's current research, Slade's body cells are disintegrating due to the many Tekno-transformations he's undergone. The next transformation could be his last.
SLADE, RINGO and STAR join the rest of the SPACE KNIGHTS at the new Command Center, where Slade's condition continues to worsen. Slade suggests that they harness the power of one of the VENOMOID spore plants to the Teknobot's Interlock Chamber, in order to force his evolution into a "super" TEKNOMAN. He has only a fifty-fifty chance of surviving the process, during which he will be immobilized for three hours. One hour after the process has begun, LANCE attacks the Command Center which, without Slade's protection, seems doomed to destruction.
Due to the psychological trauma inflicted by SLADE'S transformation into TEKNOMAN-PLUS, he doesn't remember that his friends know him by his Tekno-name (Slade). He insists on being called by the only name he remembers -- NESS. Meanwhile, the alien spore plants growing all over the planet are about to mature into Tekno-pods, capable of transforming all the humans on Earth into mutant Teknomen, slaves of the VENOMOID WARLORD, DARKON.
Because he has assumed his TEKNOMAN mode, SLADE'S memory loss has worsened and he momentarily forgets that he has the ability to transform into the TEKNOMAN-PLUS mode. So when he confronts SABER (in his "normal" Tekno-mode) Slade is no match for his twin.
SLADE and the other SPACE KNIGHTS join forces with the late CAPTAIN O'ROURKE'S commando squad in an effort to regain access to one of the Space-Ring's launching ports. One member of the squad is ANGELA, O'Rourke's widow. SWORD, meanwhile, is destroying the ports before the Earth force can get to them.
Releasing SABER from his prison, DARKON imbues him with the same super-evolved Tekno-powers that SLADE now possesses as TEKNOMAN-PLUS. Though Saber knows that the physical stress caused by the acquisition of these new powers may lead to his own destruction, he gladly accepts them as the edge he needs to destroy his twin brother.
On board the "Blue Earth," RINGO and BALZAC run into SWORD (a.k.a. KATHERINE), who attempts to destroy them in order to protect her master, DARKON. In the ensuing battle, Balzac and Ringo are badly injured and Sword is destroyed.