After Clark rescues Lana from the eye of the storm, he discovers the storm's wrath has unleashed the spaceship into the fields and buried his father alive along with the unscrupulous reporter who has discovered Clark's secret. Meanwhile, Lex is wracked with guilt over his father...

Clark becomes frightened by his uncontrollable new gift of heat-vision, which allows him to start fires using his eyes, as this new found power sets his classroom and the Talon on fire. Jonathan then comes to the conclusion that his heat-vision occurs during thoughts of sex, as the first time he was watching a sex-educational video, while the second time, he was with Lana. Meanwhile, Lex is seduced into marriage by Desiree Atkins, a woman who possesses Kryptonite-enhanced pheromones that can convince any guy to do anything. After she marries Lex, she attempts to have Jonathan kill him so she can inherit his wealth.

After one of Clark's friends discover the spaceship in the cornfield, Clark goes against his parents wishes and reveals his secret, but is shocked when the reaction he gets makes him question his friend's loyalty.

The school unknowingly uses red kryptonite in the class rings and its effect on Clark stuns everyone as he turns into a rebellious teenager who decides to use his powers for evil instead of good. Lana finds herself drawn to the new Clark who declares his love for her. Meanwhile Lex is at odds with his father about taking over his buisness.

Clark discovers someone has been leaving love notes for Lana at her parents' grave, whilst she follows the stranger to his home and discovers his parents keep him locked in chains. Clark and Lana break into the house to save him, but realize why he was locked up...

Martha goes to her estranged father for financial help. Clark is thrilled at the prospect of meeting his grandfather but Jonathan's refusal to see the man prompts Clark to force a reunion. Lana discovers an old photograph that suggests her father may still be alive...

A mysterious woman shows up claiming to be Clark's mother, prompting the Kents to tell Clark what happened after they discovered him in the cornfield that fateful day. Clark discovers why his father hates the Luthor, how his adoption was fixed, and who really rescued Lex from death...

Clark pushes his abilities to the limit to save his telepathic young friend Ryan from an evil doctor who wants to control the boy's abilities. Meanwhile, Nell tells Lana they are moving to Metropolis...

When Clark tries to warn Lana and Chloe about Ian, an overachieving student who is surreptitiously dating both girls, they realize too late that he was right. Meanwhile Lex loses his temper, landing him in an anger management class where he meets an interesting new woman...

Clark falls into a cave and discovers two hidden treasures - ancient Indian writings that hold the key to his identity, and a beautiful girl whom he believes to be his soulmate. Desperate to preserve the writings, Clark enlists Lex's help to stop Lionel from demolishing the cave...

Whitney returns home from the Marines looking to rekindle his relationship with Lana but his suspicious behavior prompts Clark to question his true motives. Lex becomes suspicious of his new girlfriend after he discovers a questionable photo of her with Lionel...

After Lex discovers that Lionel installed cameras in the mansion, he hires some thugs to bug Lionel's office, but things get out of control when Lionel and Martha surprise the thugs and are taken hostage. Clark must figure out a way to save his mother without exposing his powers and sees his chance on an adjacent tall building - if only he could make the leap in a single bound... Meanwhile Lana meets her estranged father Henry Small, while Clark and John have problems over Martha's new job working for Lionel.

When Lionel is shot, Jonathan is arrested, but after Clark and Pete perform their own crime scene investigation, they realize that more than one person had the opportunity to kill Lionel - including Lex. Meanwhile, Lana is suspicious after she asks her father to take on Jonathan's case and he declines for mysterious reasons...

A strange parasite invades Chloe and Pete's body and feeds on the teen's adrenal glands, causing them to shake off their inhibitions and engage in wild and dangerous behavior. Meanwhile, Clark gathers his courage and asks Lana for a date, which she eagerly accepts. Before he is converted by Red Kryptonite by Pete...

When Lex finds his long-lost brother Lucas, he brings him home in the hope that the two of them can unite against Lionel. A dangerous situation ensues, however, leaving Lex to wonder whom he can really trust. Clark decides to take a job at the Talon...

Clark rushes to find an antidote after Martha is infected with a toxic virus and falls into a coma, but when Clark also falls ill, it is up to Jonathan to find a cure in time. To further complicate things, Dr. Bryce demands an explanation from Jonathan when he refuses to let her treat Clark...

Determined to find out where he came from, Clark travels to New York to meet Dr. Swann, a brilliant scientist who holds a message for Clark from Krypton. Lana decides to move out of Chloe's house after the two girls get into another argument about Clark...

Clark's new schoolmate uses heat-vision to prove that he's an alien, but Clark suspects he's not from his own planet - but from Krypton, instead. Meanwhile, Helen asks Lex some hard questions...

After Lana is almost assaulted, Clark loses control and injures the boy - leaving the Kents open to be sued for punitive damages that could cost them the farm. Helen's ex-boyfriend arrives in town and stabs her, prompting Lex to take the law into his own hand...

Clark stumbles upon a robbery of a LuthorCorp truck carrying kryptonite and is stunned to realize he can't stop the thieves because they are as strong as he is. To keep Clark from going to the police, the thugs attack Jonathan and Martha...

After Lana is visited by the ghost of a childhood friend, she turns to Clark for help but he realizes the little girl is actually a kryptonite-enhanced clone, he rushes to save Lana before the revenge-seeking child harms her. Lex uncovers Lionel is responsible for the clone research...

Dr. Walden wakes up from his coma and tells Lex and Lionel that Clark is an alien and must be destroyed. Meanwhile, a romantic encounter between Clark and Lana hints at a promising future...

A sense of foreboding surrounds Smallville as Clark must choose between staying with Lana and his family or fulfilling his destiny to rule the Earth. Lex and Helen plan their upcoming wedding, whilst a hurt Chloe considers Lionel's offer to investigate...