THE 90-MINUTE SEASON FINALE IS PACKED WITH MURDER, BETRAYAL AND AN UNFORGETTABLE GRADUATION DAY FOR ALL – Clark’s (Tom Welling) high school graduation ceremony is interrupted by a second meteor shower that hits Smallville. Clark goes to the caves to confront his father Jor-El, who says that if Clark does not reunite the three Kryptonian crystals, Earth will be annihilated. Meanwhile, Lex (Michael Rosenbaum) helps Lana (Kristin Kreuk), out of a bloody situation she finds herself in. His motives, however, are not solely in her best interests. As disaster looms, Chloe (Allison Mack) and Lois (Erica Durance) try to find Lana while Clark attempts to reassemble the stones, and someone makes an unexpected return to make things unpleasant for the Kents.
GENEVIEVE ATTACKS LANA TO GET THE CRYSTAL – Clark (Tom Welling) must stop the school photographer after he sets up a fake high school and uses his ability to petrify people to kidnap students – including Chloe (Allison Mack) and Lana (Kristin Kreuk) – to keep the glory days of high school going forever. Meanwhile, Lex (Michael Rosenbaum) and Lionel (John Glover) are kidnapped and tortured by the Teagues in an effort to find the Kryptonian artifact.
CLARK AND LANA FIND AN ABANDONED BABY IN THE CORNFIELD – Clark (Tom Welling) and Lana (Kristin Kreuk) discover an abandoned baby in a field and take him back to the Kent farm. However, when the baby ages from a newborn to a 7-year-old in less than a day, it becomes clear he is aging at an abnormally rapid rate and they turn to Lex (Michael Rosenbaum) for help. Meanwhile, Genevieve (Jane Seymour) suspects Lex has the Kryptonian artifact from China and threatens Lionel (John Glover) to either recover it, or risk putting Lex’s life in danger.
CHLOE HELPS CLARK LEARN ABOUT HIS SUPERPOWERS AFTER HE LOSES HIS MEMORY – Kevin, a boy who has the power to wipe out people’s memories temporarily, turns his powers on Clark (Tom Welling) and accidentally causes him to have total amnesia. Chloe (Allison Mack) looks after him and teaches him about his superpowers while simultaneously trying to keep them secret. On his trip down memory lane, Clark meets Lana (Kristin Kreuk) and falls in love all over again. Lex (Michael Rosenbaum) takes advantage of the situation and attempts to unravel some secrets.
LIFEHOUSE ROCKS THE SMALLVILLE PROM – On the eve of the Smallville High School Prom, stuck-up candidate for Prom Queen Dawn Stiles is pulled into a coma when she crashes her car into a ravine filled with kryptonite. While her body lies in a coma, Dawn finds that her spirit can possess the bodies of others. To continue her quest to become Prom Queen, Dawn possesses the bodies of Martha (Annette O’Toole), Lana (Kristin Kreuk), Lois (Erica Durance), and Chloe (Allison Mack) in turn, leaving Clark bewildered at the abrupt personality change of his family and friends.
LEX’S DARK SIDE EMERGES AFTER A KRYPTONITE EXPLOSION – A black Kryptonite explosion splits Lex (Michael Rosenbaum) in two and his evil side – Alexander – is released. Alexander imprisons Lex in the mansion then gives full vent to his evil side – he threatens to evict Lana (Kristin Kreuk) from the Talon unless she becomes his mate, jousts with Lionel (John Glover) , and tries to kill Clark (Tom Welling) and Chloe (Allison mack) when they figure out his secret.
LOIS LANE’S SISTER, LUCY, COMES TO TOWN – Lucy Lane, Lois’ (Erica Durance) younger sister, comes to Smallville but Clark (Tom Welling) catches her stealing money from the Talon to pay off a European crime syndicate. Lex (Michael Rosenbaum) offers to help but everything is not what it seems. Meanwhile, a thief breaks into Lana’s (Kristin Kreuk) apartment and steals the crystal, and Jason (Jensen Ackles) suspects Lionel (John Glover).
CLARK AND LANA HEAD TO CHINA IN SEARCH OF A KRYPTONIAN CRYSTAL – After Clark (Tom Welling) receives a message from the recently-deceased Dr. Swann, he and Lana (Kristin Kreuk) follow Jason (Jensen Ackles) and Lex (Michael Rosenbaum) to China in search of one of the Kryptonian Crystals. Lana is tortured, causing Isobel to emerge and wreak havoc in her search for the crystal.
SUPERDOG TO THE RESCUE – Lois (Erica Durance) accidentally hits a dog and brings it back to the farm to heal, but Clark (Tom Welling) quickly realizes it has super-strength. He investigates and discovers it was part of an aborted LuthorCorp experiment…and that robbers are using the dogs to help them steal money. Meanwhile, Lana (Kristin Kreuk) wonders what Jason (Jensen Ackles) is up to with his mother, and Jason is forced to ask Genevieve (Jane Seymour) a few questions of his own.
CHRIS CARMACK (“THE OC”) GUEST STARS – Clark (Tom Welling) is approached by Metropolis University for a football scholarship and meets Geoff, a former outstanding Smallville High player who gives Clark a taste of the luxurious life as a football star. However, Geoff is revealed to be a meteor freak and is secretly using his abilities to gain an unfair advantage on the field. Clark reconsiders his plans to pursue football in college. Meanwhile, Lana (Kristin Kreuk) gets upset over Lex’s (Michael Rosenbaum) investigation into Genevieve (Jane Seymour). She confronts Lex, who gives her a reason to reconsider her trust for the Teagues.
LANA IS ATTACKED AND ALL FINGERS POINT TO ALICIA – When a mysterious killer strikes at both Lana (Kristin Kreuk) and Jason (Jensen Ackles), Alicia (Sarah Carter) is the leading suspect and even Clark (Tom Welling) comes to doubt her innocence. Feeling betrayed, she secretly tricks Clark into revealing his powers in front of one of his friends. And Genevieve (Jane Seymour) returns to town with an offer for Lex (Michael Rosenbaum), who in turn has an offer for Jason.
ALICIA RETURNS TO SMALLVILLE FOR CLARK – Claiming to be cured, Alicia Baker (Sarah Carter) is released from Belle Reve hospital and comes to Smallville to rekindle her relationship with Clark (Tom Welling). Initially skeptical, Clark finds himself enjoying dating someone who knows his secret, but when she pushes for more, he hesitates, causing her to use red Kryptonite on him. Clark, under the influence of red Kryptonite, whisks Alicia off to get married in Las Vegas. Meanwhile, Lana (Kristin Kreuk) ponders whether or not to take her relationship with Jason (Jensen Ackles) to the next level in order to win him back. Lex (John Glover) is unimpressed with Lionel’s (John Glover) claims of being a changed man.
TOXIC WASTE – A LuthorCorp experiment is released into the atmosphere – a toxin that causes its victims to hallucinate their worst fear. Chloe (Allison Mack), Clark (Tom Welling), Lana (Kristin Kreuk), and Jason (Jensen Ackles) all fall victim to the toxin, and Lex, desperate to find a cure, takes a dangerous antidote. Meanwhile, Lionel (John Glover) is released from prison and his conviction overturned thanks to a mysterious benefactor.
JANE SEYMOUR GUEST-STARS – Lex (Michael Rosenbaum) is accused of killing a young woman and suspects that Lionel (John Glover) is behind it. Lionel, whose liver has miraculously healed, claims to be a new man and aids Clark (Tom Welling) in finding the person responsible for framing Lex. Meanwhile, Jason’s (Jensen Ackles) mother, Genevieve (Jane Seymour), comes to town to visit her son and his new girlfriend. Jason suspects her motives and worries that his seemingly accidental meeting with Lana (Kristin Kreuk) in Paris might have been all a set up by his mother.
A WITCH HUNT IN SMALLVILLE – After Lana (Kristin Kreuk) reads from a spell book written in the 1600s, she, Lois (Erica Durance) and Chloe (Allison Mack) become possessed by witches that had been burned at the stake. The three witches have come back seek revenge and search for the powerful Kryptonian crystals, wreaking havoc on the town in the process. Clark attempts to stop the witches but they strip him of his powers and force him to reveal the location of the crystal he hid in the cave.