Clark discovers that a fellow student Greg (guest star Chad E. Donella), having been attacked by kryptonite-affected bugs, has taken on the "eat, molt, mate, die" life cycle of an insect. Now Lana is his prey.

Who's Greg? Although they were all friends in elementary school, Greg's behavior has changed as he's become more obsessed with insects. His mom wants to send him to military school. At night as he drives his beloved insects to a safe haven (in what else...his vintage VW Beetle) the bugs escape in the car and swarm, attacking him. Now weirder than before, Greg returns home and traps his mom in a web, killing her.

What's up with Whitney? Greg makes a study date with Lana, his next intended victim. Jealous Whitney warns Greg to keep away from her. Later, as Whitney drives down a country road, Greg leaps from a tree, causing the truck to rollover. The Kents drive up right behind, and Clark pulls Whitney from the burning truck, saving him by shielding Whitney from intense flames.

What's up with Lex? As Clark's friend, Lex visits Lana, dropping clues about the scarecrow incident in hopes of getting Lana and Clark together. When Clark visits Lex at the mansion, Lex plays matchmaker again, giving Clark Lana's kryptonite necklace he's kept in a lead box. Lex wants Clark to return the necklace to Lana, explaining what happened with Whitney and the scarecrow prank.

What's up with Lana? Lana questions Whitney about the prank. He admits his guilt and tells Lana he lost her necklace. Lana visits Clark at the barn to apologize for Whitney about the scarecrow incident. She really came to see Clark, and is beginning to question her relationship with Whitney.

Clark discovers Greg's plan: Greg attacks Clark and his dad from the rafters of the Kent's barn. A struggle sends Mr. Kent falling, heading for the sharp blades of some farm equipment. Clark cushions Dad's fall with his own body, saving his dad from impalement. Reporter Chloe pieces together Greg's bug life. They guess Lana is his next prey. Whitney is attacked by Greg and Lana is taken to Greg's old treehouse. Clark finds Lana there, "webbed" by Greg. Clark chases Greg into the old abandoned foundry, which is littered with kryptonite, weakening Clark. From a lead protected corner of the foundry, Clark throws Greg across the room. A large piece of metal falls, crushing Greg into a thousand bugs. Whitney frees Lana from her web, leaving Clark in the shadows.

How it ends: Clark leaves Lana's necklace on her front door, and backs off. She opens the door and finds it with a smile, as Clark walks home.