Plot

The Kents are visited by a Kryptonian girl named Kara who tries to convince Clark to leave Earth. Lionel Luthor is put on trial for his crimes but he has one final trick up his sleeve which causes Clark to question his friendship with Lex.

At the Kent farm, Clark Kent is surprised in the middle of the night by a naked young woman claiming that she is Kara from Krypton, and asking him to go with her somewhere through the Kawatche caves to be "re-born" with the spirit of Jor-El. Kara also forces Jonathan to reveal the secret deal he made with Jor-El at the beginning of the season. Meanwhile, Clark decides to testify against Lionel to keep him in prison. Lionel sends a key of the secret chamber in the Luthor Mansion to Clark where he finally discovers the reason for the last three years of Lex's personal investigation of him, and he ends his friendship with Lex. Agent Loder continues investigating Clark's origins, until Kara finds him eavesdropping on the Kents and she eliminates Loder for good. Also, Lana leaves for Paris and Chloe and her father are included in the witness protection program. Events come full circle as Jonathan unsuccessfully tries to stop Clark from traveling through a dimensional gateway in the cave wall, Martha observes a Kryoptonia symbol that appears in a open field, Lex is alone in the mansion when he had a drink of brandy which is poisoned, Chloe and her father arrive at a FBI safe house... which explodes with them still inside, and Lionel accepts his new look in prison, but satisfied knowing that his revenge against all those involved with his incarceration has been accomplished.—Claudio Carvalho, Rio de Janeiro, Brazil

A young woman walks out of the woods naked and uses super-strength to total a car, killing the passengers. She then walks to the Kent Farm and greets Clark by name, introducing herself as "Kara from Krypton." She claims to have come from the caves and tells the Kents she's here to take Kal-El home to answer all his questions. She becomes angry when Jonathan enters the conversation and disappears when Lex arrives.

Clark offers to testify at Lionel's bond hearing that he ordered the doctor to increase the voltage even when the doctor warned that it could have injured Lex. Lex guesses that Clark hid the knowledge of Lionel's murder of his parents. Clark explains he was concerned for Lex's fate and Lex accepts that.

Even from jail, Lionel expects FBI Agent Loder to continue investigating Clark. Loder refuses, believing that Lionel is powerless.

Kara takes Clark flying to the cave and says that she's been in the cave since the meteor shower, waiting until the time is right. Clark declines her offer to enter a passage to find out everything.

Lex visit Lionel in jail. Lionel reveals to Lex that he was diagnosed two years ago with a degenerative liver disease and nothing can save him, but Lex doesn't believe him.

The next day Kara tells Jonathan that he "broke the covenant" and reveals that in return for the power he received to bring back Clark, he promised to return Clark to his father Jor-El. Clark and Martha are appalled and Jonathan stammers that he didn't believe it would be so soon. As Loder listens in, Kara senses him and kills him by turning his car and everything in it to dust. Martha is upset that Jonathan made the deal and kept it secret from her.

Jonathan takes a tea cup to Chloe and asks her to run a check on Kara's fingerprints, while Lana arrives at the farm and asks Clark to take her to the airport the next day. She asks him to tell her whatever he has to tell her before she's gone. She sees Kara and Clark explains that she is his cousin from California. Lana suggests that she should find someone else to drive her if he has visitors, but Clark assures her that even though it will be hard for him to see her go, he wants to be there for her. She seems pleased and he promises that they will talk in the car on the way to the airport.

Kara warns him again that even though Lana loves him, their love is not meant to be. Everyone he knows will eventually betray him, Kara says, but the love that they will know will be like nothing else. Kara tells Clark that they are the last Kryptonians, and they must preserve their race.

Clark receives a package from Lionel with a key. Lex and Chloe review medical records, but Lex is still determined that he and Chloe should send him to prison, and Chloe vows to testify no matter what, as Lionel has threatened her long enough.

Clark confronts Lionel, who sends him to the room Lex has been using for his investigation of Clark. Lex walks in and tries to explain that this room is about him and his countless brushes with death, but Clark is extremely upset. He doesn't believe Lex and leaves, convinced that Lex has been his friend all this time just so he can investigate him.

Clark goes home to his loft where he tells his mother about Lex's betrayal. He is considering going with Kara when he suddenly remembers Lana. She took a shuttle to the airport and Clark arrives just in time to see her saying goodbye to Lex. Lana sees Clark and crosses the street to him, but he disappears without saying goodbye, and Lana finds a white rose he was going to give her.

Clark is late arriving at the courthouse and Lex worries that he has changed his mind, but he arrives just in time. Lionel is denied bail, but Clark tells Lex that their friendship is over.

Back at the farm, Clark is still in anguish over Lex's betrayal and Lana's departure. Kara is there to comfort him and tempts him further by claiming that Lara's love lives on. Clark says that he is ready. Chloe arrives at the farm and tells Jonathan that the fingerprints belong to Lindsay Harrison.

Kara and Clark go to the caves to prepare to "leave" by joining hands and opening a fissure in the cave wall. Jonathan arrives at the caves to expose Jor-El's deception. Jonathan tells Clark that Kara is really Lindsay Harrison a girl who disappeared on the day of the meteor shower. Clark refuses to enter the fissure. Jor-El dissipates Kara, explaining that she served her purpose. Then he strangles Jonathan with a rope of energy and threatens to kill him if Clark doesn't agree. Despite Jonathan's pleas, Clark enters the light and disappears.

Martha runs outside to see a Kryptonian symbol burned into the fields; the Sullivans enter protective custody only to have their new house blow up as soon as they enter. Lionel has his head shaved bald, Lex chokes after drinking a glass of brandy, and Jonathan remains unconscious on the floor of the cave while Clark floats in a void and Jor-El promises his son that he "shall be reborn."