Clark reveals his secret to Lana, Jonathan and Lex learn the results of the senatorial election, and there is a tragic car accident on the highway that takes the life of someone Clark loves, forcing Clark to appeal to Jor-El for help.

In an attempt to cheer up Clark, Lois convinces him to attend their five-year high school reunion. A visit back to the home of the Crows has Clark remembering old times with Lana and Chloe, while Lois is furious that no one remembers her five days as a student. Brainiac 5.0 uses his Legion ring to visit from the future and takes Clark through his past, present and future. He shows Clark what really happened the night Jonathan died, Oliver’s current pain and Clark’s future at the Daily Planet with Lois and his role as Earth’s favorite red and blue superhero.

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.

After a nightmare, Clark goes to the cave to confront his father Jor-El. Jor-El warns that the crystals have fallen into human hands and have triggered a new meteor shower which will annihilate the Earth unless he reunites the three crystals. Meanwhile, Lex helps Lana, who has apparently commited murder, but then turns against her to get possession of her Kryptonian stone. As disaster looms, Chloe and Lois try to find Lana while Clark attempts to reassemble the stones, and Jason returns to make things unpleasant for the Kents.

When Zod and the Kandorians launch their brutal attack on Earth, Chloe calls in some old friends to join the fight against the aliens. Clark and Zod face off in an epic battle for the control of Earth.

The story of Clark Kent culminates in this epic two-hour series finale as Clark takes the last step to becoming the Man of Steel.

When a mysterious killer strikes at both Lana and Jason, Alicia is the leading suspect and even Clark comes to doubt her innocence. Feeling betrayed, she secretly tricks Clark into revealing his powers in front of one of his friends. And Genevieve returns to town with an offer for Lex, who in turn has an offer for Jason.

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.

The Persuader attacks Clark; Chloe, as Brainiac, tells Davis he is Doomsday and that he was created to destroy the "other Kryptonian" and the world.

A man named Sylvester Pemberton tracks down Chloe and tells her he knows about her team of superheroes and needs their help. However, before he can explain who he is, he is attacked and killed by Icicle. Clark and Chloe's investigation leads Clark to the former headquarters of the Justice Society of America where he meets up with Nelson AKA Dr. Fate, Carter Hall AKA Hawkman and Courtney AKA Star Girl. Courtney pleads with Hawkman and Dr. Fate to help her catch the killer that is targeting their group but they are reluctant to resume their duties as superheroes. Clark, John Jones, Green Arrow and Chloe team up to help the JSA stop Icicle before he murders another member of the group. Meanwhile, Lois receives a package from a mysterious agency called Checkmate, run by Amanda Waller.

Believing that key information about his father's past was lost when his memory was erased, Lex decides to join an experimental program with Dr. Garner to regain the information so he can turn his father over to the FBI. Knowing that Lex will discover his secret if he regains his memory, Clark tries to stop him but is caught by Lionel and the doctor and exposed to the same radical treatment so that Lionel can solve the mystery of Clark's past.

Clark is drawn to the state penitentery by one of the kryptonian crystals, which Lionel is using to switch bodies with Lex. Clark intervenes and Lionel enters his body instead. While Lionel uses his newfound super-powers to regain his lost fortune and alienate Clark's friend, Clark must convince his parents that he is the "real" Clark and reverse the processs, while avoiding murderous convicts.

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.

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

Unexpected guests crash Chloe and Jimmy's wedding; Oliver thinks he has found Lex and sets out to confront him, but he is shocked to find Lana instead; Lois and Clark grow closer.

Clark travels to New York to meet Dr. Swann, a brilliant scientist who holds a message for Clark from his home planet. Meanwhile Lana decides to move out of Chloe's house after they get into an argument about Clark.

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 prepare for their marriage, and Chloe considers Lionel's offer to investigate Clark.

Three of Clark's former opponents approach Lex to enlist his help in luring Clark to the hospital after they hear that Lionel has requested Lex be given electroshock therapy to erase his memory. However, the plan goes awry when the villains double-cross Lex and use kryptonite to steal Clark's powers. Meanwhile, Lana meets a mysterious stranger in the hospital.

A black kryptonite explosion splits Lex 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 from the Talon unless she becomes his mate, jousts with Lionel, and tries to kill Clark and Chloe when they figure out his secret.

Jor-El strips Clark of his powers, making him human. Delighted to finally be normal, Clark pursues a relationship with Lana sans secrets. However, after Lana, Jonathan and Martha are taken hostage by three thugs, Clark must figure out how to save his family without his super powers.

Jonathan's wallet is stolen by a super-speed thief, Bart Allen, who is faster then Clark. Bart comes to the farm and becomes friends with Clark, but Bart returns to crime when he sees an ancient manuscript that Lex has. As Clark soon realizes, the manuscript holds a map to one of the kryptonian crystals and he must go up against Bart to recover it.

Professor Fine has unleashed a virus that will kill millions. Clark must put a stop to him, while Lex wonders what happens when he will tell Lana his newest secret.

Clark receives a package containing the crystal that Tess found in the Arctic; the crystal activates, sending Clark and Lois to the Phantom Zone, where they run into Kara (Laura Vandervoort); Zod's wife, Faora, takes over Lois' body.

An explosion at LutherCorp injures Oliver and kills all the board members.

Linda Lake returns to Metropolis and threatens to expose Clark’s secret unless he promises to give her exclusive information on the red-blue blur so she can become a star reporter again. Refusing to be blackmailed, Clark tells Lois his secret and asks her to write his story for The Daily Planet.