A powerless Clark is trapped in the "Phantom Zone" surrounded by the criminals his father imprisoned there. However, an unexpected ally comes to his aid. Meanwhile, Zod in Lex's body advances his plan to transform Earth into a new Krypton, while using Lana to produce an heir.

In the aftermath of Zod's activities, Clark develops a new power. Lois gets a new job, Lana takes a new step in her relationship with Lex, and Lex has to deal with a new danger. Meanwhile, an old friend of Lex's arrives in Metropolis.

Clark and Chloe pursue a plant creature that uses male humans to recreate, one which has taken Jimmy Olsen as its next human breeding ground. Meanwhile, Oliver Queen asks a reluctant Lois to be his date at a charity ball held by Lex.

The mysterious Green Arrow steals a necklace from Martha, and both Lois and Clark resolve to find out who the vigilante is. While Clark determines Green Arrow's true identity, Lex continues his investigation of the mysterious black box while Lionel warns Lana against him.

Lex and Oliver Queen return to their old prep school for a reunion, but Oliver's old friends (and Lex's old enemies) start dying in mysterious accidents. Meanwhile, Clark learns that someone... or something may have left the Phantom Zone with him.

After escaping from the Phantom Zone, Raya comes to Smallville to visit Clark. Raya and Clark grow close, and Raya reveals how to repair the Fortress of Solitude. Unfortunately, Baern, another escapee seeks out revenge on Clark and Raya for his time spent in the Zone.

After being shot while stopping a carjacking, the Green Arrow begins acting strangely. Chloe and Clark investigate and find Oliver is taking a super drug that while healing his wound, has some dangerous side effects.

One of the escapees from the Phantom Zone has killed the crew of a ship in Seattle. Clark confronts the killer who feeds on the bones of his victim. In Smallville, a patient in LuthorCorp Labs escapes experimentation and seeks revenge on Lex by trapping him in a dimension where he can see and hear those around him, but they cannot see him.

An illegal immigrant comes to Clark for help, escaping from a nearby farm where he's working... a farm that houses a dark secret.

A Daily Planet gossip columnist uses her special power to overhear a conversation between Lana and Chloe, and publishes the conversation... where Lana admits having doubts about marrying Lex. While Chloe investigates the reporter, Lois asks Clark to help her investigate the mysterious Green Arrow bandit when she suspects he may be Oliver Queen in disguise.

When Lex's Level 33.1 project comes to fruition, Oliver Queen must bring together several of Clark's "heroic" super-powered allies together: Arthur Curry, Bart Allen, and Victor Stone.

Clark is in his barn one moment... and the next finds himself in a psychiatric hospital where he discovers he's been suffering from delusions that he came from another planet and has super-powers.

Clark is once again exposed to red kryptonite, and his "other self" goes on a rampage of sorts on Valentine's Day, kissing the women he's most attracted to and expressing his uninhibited feelings for the various relationships around him.

Lana has a stalker which leads her to an unexpected hideout. Also, Chloe has to reevaluate her feelings for Clark after she and Jimmy break up due to Jimmy's belief that she isn't really over Clark.

A boy named Tobias was blinded by the meteor shower but given the ability to identify other meteor freaks. Lex is using Tobias to locate other people with abilities so that he can perform experiments on them. Lana learns of Tobias and is fearful that he will name Clark as a freak, so she offers him a cornea transplant to keep him quiet. But Tobias has some surprising news.

Clark has second thoughts about Lana marrying Lex, and Lana has the same concerns. Meanwhile, the doctor involved in the secret behind Lana's pregnancy threatens Lex with his knowledge.

Clark and Chloe find an escaped Zoner named Titan who is the star of a secret fight club that puts its death battles on the internet. Lois can tell that there is a story and goes to investigate, where she is put in the ring to fight. Clark goes in as a super-powered fighter to take on Titan but ends up against a different opponent instead.

Lex discovers that Chloe's mother has special abilities and forces her to help him in exchange for Chloe's life. However, she has a trick or two of her own to use to escape.

Lex and Clark get a chance to hash out their differences... when they're both trapped in a cave after an explosion, and Clark is unable to get them out without revealing his powers.

Lana and Lionel have a secret meeting, after which Lana is shot. While Jimmy is observing photos of the encounter, he is knocked unconscious. While unconscious Jimmy dreams about what life in Smallville would have been like in the 1940s. Clark is a reporter at the Daily Planet, Lana is a siren who planned the demise of her magnate husband Lex, and Lois is a singer at a bar that Lionel owns.

Lex tries to turn a soldier that supposedly died in Afghanistan into a "super-soldier." A senator threatens to tell the world about Lex's labs, prompting Lex to send the "soldier" to kill the senator. Lois sees the attack and becomes the soldier's next victim.

Clark discovers the reason Lana married Lex then and sets out to kill Lionel. Lex tries to use DNA from the last phantom to power his super-soldiers. Lois goes to a dam to search for Lex's lab but is caught by a security guard and fatally injured. Chloe's power is discovered.

During Clark's battle with the last Phantom Zone wraith, Lex is rescued by a mysterious woman. She then goes to the Kent farm and reveals she is Clark's cousin, Kara, from Krypton.

Clark and Lois meet Smallville's newest arrival face-to-face, and she has some surprising news. Clark decides to leave Smallville and continue with his superhero training but Jor-el informs him that a new Kryptonian menace has arisen.

Kara takes to life in Smallville by getting a job at the Talon, and entering the Miss Sweet Corn Pageant as a contestant, overruling Clark's objections. However, Lex takes an interest in her and three of the other contestants discover she has super-powers and decide to use her to steal a valuable time capsule.

Dr. Curtis Knox says he can "cure" someone from being a "meteor freak," changing their lives. Chloe takes an interest in this, but Dr. Knox may have another secret.

When a movie is shot in Smallville, Clark is forced to secretly use his powers to save someone from a runaway car... but somebody is looking and becomes Clark's biggest fan. Meanwhile, Lionel's fate is revealed.

Kara goes to Washington to look for her missing crystal, but is captured after she breaks into the lab. She's sedated with a truth serum that has kryptonite in it, which makes her relive a trip to Earth from the past. In this past trip she followed Lara, Clark's biological mother, to the Kent's farm. Clark saves Kara, but also ends up being affected by the serum when he burns it with his heat vision.

Lana absorbs Clark's powers during a lightning storm, which she uses to break into Lex's safe and steal some incriminating evidence. After being turned away by Grant at the Daily Planet, who won't accept her stolen evidence, Lana goes after Lex herself. Clark tries to rescue Lex, but must first battle the super-powered Lana.

Clark hears his mother's voice trapped in Kara's crystal, and releases her. She gives him Jor-El's ring made of Blue Kryptonite, which strips him of his powers.

A mysterious man who claims to be a product of Lex's latest project plants a bomb on Chloe and uses her to force Lois to get the truth from Lex.

Chloe begins to notice that Clark's not acting like himself. Bizarro enlists the help of Brainiac.

When Green Arrow's band of heroes thwarts his efforts once too often, Lex employs a super-powered vigilante to take down the Emerald Archer.

Lex tracks the amnesiac Kara to Detroit, where Lois follows him. An obsessive busboy infatuated with Kara shoots Lex, and Chloe has to determine whether to heal him or not.

Pete Ross returns to town and finds a number of surprising changes since his departure. Besides resolving his feelings toward Clark since he learned of his friend's secret, Pete has to deal with the acquisition of a superpower of his own.

Lionel has Clark kidnapped, and when Chloe and Lana confront him, he makes them think Lex is the culprit. Chloe and Lana then beg Jor-El to restore Kara's memory because she's the only person who can rescue Clark.

Clark must learn a new superpower as he and Kara join forces to take on Brainiac, putting the lives of their friends in danger.

No one is safe when Lex seeks the secret of Veritas, and Clark tries to stop him.

While Clark seeks out Brainiac to force him to fulfill his side of their bargain and restore Lana, Chloe and Jimmy go up against the government.

When Clark wonders if the world would be better off if he never came to Smallville, Jor-El shows him what life would have been like if he had never existed.

After Lex is attacked by a mysterious stranger, he and Clark both discover the last surviving member of the Veritas group who holds the secret to controlling the Traveler.

Lex is taken to the Fortress to fulfill his destiny, while Lana awakens from her coma and Chloe is arrested by the government.