Vortex Clark rescues Lana from a destructive twister that tears through town, but his good fortune is short-lived as he discovers that his dad is missing. Meanwhile, Lex's hesitation in a moment of crisis leads to serious injuries to his own father.
Heat Lex impulsively marries a woman two weeks after he meets her, unknowingly moved by her ability to control a man's mind by emitting a kind of pheromone mist. He's also unaware that she plans to kill him so that she can inherit his fortune. Elsewhere, Clark has trouble controlling his newest power - heat vision.
Duplicity Clark tells Pete about his extraterrestrial powers after Pete finds Clark's spaceship and insists on hiding it in a shed in his own yard, but the craft is soon stolen by a scientist. Meanwhile, Lionel Luthor claims he wants to spend more time with Lex; and Lana is suspicious of her aunt's new boyfriend.
Red Clark's behavior radically changes after getting his school ring, which has a red kryptonite stone in the setting. His reckless conduct threatens the safety of his family and friends. Meanwhile, a new student at Smallville High is hunted by a psychotic U.S. marshal.
Nocturne A teen who is kept locked in the basement of his parents' house during the day sneaks out at night and leaves love letters for Lana at her parents' graves. Meanwhile, Lionel Luthor hires Clark's mother as his personal assistant.
Redux Family secrets abound as Martha goes behind Jonathan's back to ask her father for money after the family's bills pile up; and Lana finds pictures of her mother with another man that were taken after her parents were married. Meanwhile, a healthy high-school student dies of old age shortly after kissing his girlfriend; and Clark has a run-in with the new school principal.
Lineage A woman arrives in Smallville and tells Clark that she's his biological mother and informs Lex that Lionel is the father. Plus, she wants Clark to take a DNA test to confirm her story. Meanwhile, Lana decides to meet the man who could be her biological father.
Ryan Clark rescues a teenage mind reader from a laboratory where a maniacal scientist performs cruel cognitive experiments on the youngster. Meanwhile, Lex crosses swords with the corrupt mayor of Smallville over a potential business deal.
Dichotic A Smallville honor student who can clone himself at will kills a teacher to avoid a bad grade, then develops a romantic interest in Chloe and Lana. Meanwhile, Martha feels guilty about her career choices after Jonathan is injured in an accident on the Kent farm while she is at work.
Skinwalker Clark meets a Native American girl in a cave and discovers drawings on the walls from the girl's ancestors that tell a tale mirroring Clark's arrival in Smallville during a meteor shower. Meanwhile, Lana learns the results of a DNA test that could prove her kinship to Henry Small.
Visage One of Clark's former adversaries returns to Smallville and causes a rift between Lana and Clark. Elsewhere, Lex accuses a woman he's dating of spying on him for Lionel Luthor.
Insurgence Lex hires goons to plant listening devices in his father's Metropolis office, but things go awry when the thugs decide to rob the tycoon's vault instead and end up taking two hostages: Lionel Luthor and Martha Kent. Meanwhile, Lana learns that her biological father's wife has agreed to meet with her, but the encounter proves to be a tense one.
Suspect Lionel Luthor is shot by an unknown assailant and Jonathan Kent is arrested for the crime after the police find him with a gun and a bottle of tequila. Meanwhile, Lex does some digging of his own and begins to suspect that someone else pulled the trigger, but his reluctance to share this information leads to a clash with Clark.
Rush A strange parasite invades Pete's body and feeds on the teen's adrenal glands, causing him to shake off his inhibitions and engage in wild and dangerous behavior. Meanwhile, Clark gathers his courage and asks Lana for a date, which she eagerly accepts.
Prodigal Lex finds his long-lost brother, Lucas, and tries to persuade his sibling to help him stage a financial coup against their father. Unfortunately, Lex's plan backfires. Meanwhile, Clark applies for a position at Lana's coffee shop.
Fever Martha is hospitalized after becoming seriously ill from exposure to kryptonite spores in the Kent's storm cellar, and Jonathan learns there are complications. Meanwhile, Lex's girlfriend is offered a lucrative position at a hospital far away from Smallville.
Rosetta After seeing a newspaper photo of a Kryptonian symbol burned into the side of the Kents' farmhouse, a reclusive physicist takes an interest in Clark and offers the teen information on his alien origins. Meanwhile, Chloe catches Lana looking through private files on her computer.
Visitor Clark thinks an awkward new student who claims to be an extraterrestrial might be telling the truth after he sees the teen start a fire with his eyes and heal a sick horse with his touch. Meanwhile, Lex's lovelife heats up when he asks Helen to move into the mansion with him.
Precipice Clark is arrested and his family faces a civil lawsuit after the teen defends Lana by hurling an unruly college student onto the hood of an oncoming police car. Elsewhere, Helen's former boyfriend arrives in Smallville and causes trouble for Lex by filing a false assault charge against him.
Witness Clark witnesses a popular Smallville baseball player steal a shipment of refined kryptonite from a LuthorCorp truck to enhance his athletic abilities. Meanwhile, Lana's relationship with her father improves, while Clark's friendship with Chloe deteriorates.
Accelerate Lana thinks she sees the ghost of a childhood friend who died years before when she's visited by a 10-year-old girl, so Clark sets out to find a logical explanation for the incidents. In other developments, Lex prepares for his wedding by meeting with an event coordinator; and Jonathan begins building a crib in anticipation of the new baby.
Calling Clark kisses Lana, then he hears a cryptic message from an unknown source that matches the ranting of a crazed linguist who was injured by a Kryptonian energy beam while inspecting the cave. Elsewhere, someone breaks into Helen's office and steals a sample of Clark's blood.
Exodus Clark learns the mysterious voice calling to him belongs to his Kryptonian father, who tells him to leave Smallville to prepare for his role as Earth's ruler. Meanwhile, Lex's wedding is jeopardized when he makes a confession to Helen that causes her to question their entire relationship.