Clark begins experiencing "vision problems" as his x-ray vision begins manifesting. Meanwhile a mysterious shapeshifter is going about town using his or her abilities to steal and get others in trouble.

A weight-obsessed teen dieting on kryptonite-infected vegetables gains her fondest dream...but must feed on the fat of others to maintain her enhanced appearance.

An experiment at the Luthor fertilizer plant makes an old friend of the Kents literally shake and jitter, and he seeks vengeance against the Luthors, who hide the secret of his transformation behind "Level Three" at the local plant.

Lex and Victoria are victims of a suspected household poltergeist. As the disturbances become more violent, suspicion lands on Amy, the daughter of a house servant who is obsessed with Lex. Not is all as it seems...

Whitney falls in with some former jocks who have kryptonite tattoos that give them the power to walk through walls. Meanwhile, Chloe is seriously injured and Lex has his own plans.

A young runaway, Ryan, has the power to read minds and flees his abusive stepparents. The Kents take him in and Clark soon discovers the boy's powers and that he's immune to them. But Ryan's stepparents have plans to use the boy's powers for financial gain against...Lex.

Former Smallville High cartoonist Justin loses the use of his hands in a hit and run accident, and develops the ability to move things with his mind. After crippling his unsympathetic doctor he returns to Smallville and hooks back up with his friend Chloe. He reveals his secret to Chloe, and then takes revenge by killing Principal Kwan, who was the driver who hit him. It turns out Kwan's son Danny was the driver. Chloe realizes Justin is responsible, and Clarks comes to her aid, knocking Justin out. Meanwhile, Lex's former nanny, Pamela, comes back to see how he's doing and to apologize for leaving him after his mother's death, bringing up some old issues for Lex. And Whitney's father passes away.

Clark gains a new power - heat-vision. As he struggles to control it, Lex gets married to the new Smallville High teacher, Desiree Atkins, little does he know that she not only has an alterior motive, but that she's coming on to Clark too.

Lana has a new stalker - a boy imprisoned in his basement by his parents who sneaks out at night to visit her. Meanwhile Lionel hires Clark's mother as his personal assistant.

Martha's father William comes to town after many years of estrangement due do his disapproval of Jonathan. Meanwhile Clark must deal with a series of old-age deaths at Smallville High, and the new principal puts his foot down.

A Smallville student, Ian, displays the ability to make clones of himself and uses his power to date both Chloe and Lana. Meanwhile Lex goes to anger management class and meets an attractive local doctor.

Lionel is shot in the manor, and Jonathan is the prime suspect.

Martha catches a lungful of kryptonite-irradiated spores and a weakened Clark is her only hope for survival.

After Lana is almost assaulted by a college student, Clark injures the boy while helping her. When the Kents are sued for damages that could cost them the farm, Clark tries to find a way out of the lawsuit. Meanwhile, Helen's obsessive ex-boyfriend comes to Smallville to win her back but when she turns him down, he stabs her, prompting Lex to take the law into his own hands.

Dr. Walden comes out of a coma with super-powers and a desire to kill Clark, piquing the Luthors' interest. The spaceship starts talking to Clark, and Helen and Lex prepare for their wedding.