Having been transported to the Fortress of Solitude, Clark is confronted by Jor-El, who tells him he cannot return to Smallville, instead he must stay and prepare to save the planet. Also, transported to the Fortress, Chloe is unable to handle the sub-zero temperature and collapses, begging Clark to use his powers to save her. Jor-El forbids him to leave, but finally acquiesces, telling Clark he must return before sunset or there will be dire consequences. Meanwhile, Lana is horrified when she sees two Kryptonian aliens emerge from a spaceship discovered in the remnants of the meteor shower. The two aliens destroy what's left of the town searching for Kal-El.

Jor-El strips Clark of his powers, making him human. Delighted to finally be a normal,a 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...

Chloe is warned by Gabriel that he is going to set off a missile and obliterate all of Smallville. Still stripped of his super powers, Clark confronts Gabriel and ends up getting shot. In the hospital, Clark flatlines and his fate is left in Jor-Ela 's hands. Meanwhile, Lex believes Lionel has the key to open the spaceship. While back at the Fortress of Solitude, a newly vamped Clark-Kal El is confronted by his late father...

A summer beach party at Crater Lake takes a dramatic turn when Lois hits her head while jumping into the lake. Before Clark can save her, a mysterious swimmer, Aquaman, a.k.a. AC, comes to her rescue, out-swimming Clark and leaving him baffled. Meanwhile Professor Fine tells Clark that Lex is behind a covert operation manufacturing weapons. AC attempts to break into the Luthercorp Marine Center in an attempt to destroy one of Lex's torpedoes and is captured by Lex...

Lana decides to enroll at Metropolis University at the last minute and is forced to join a sorority to find housing at such a late date. However, her new sorority sisters offer her more than a place to crash after they turn her into a vampire and instruct her to kill Clark. Meanwhile, Chloe applies for an internship at the Daily Planet, but the newspaper's formidable editor may be more then she can handle.

Clark and Jonathan are thrilled when Senator Jake Jennings, Jonathan's oldest friend, arrives at the Kent farm looking for support in his re-election campaign. However, after a young girl turns up dead, it is revealed that she was a stripper and Jenningsa ' mistress, which makes him the prime suspect. Searching for answers, Chloe convinces Lois to go undercover as a stripper...

Clark is exposed to silver kryptonite, causing him to have paranoid delusions. The silver kryptonite makes him believe that Chloe is going to reveal his secret, Jonathan is scheming against him with Lionel and Lex and Lana are having a secret relationship. Chloe and the Kents frantically search for a cure, but it is Professor Fine who comes to Clark's rescue - but not without an agenda...

After Martha contracts a strange disease and is given hours to live, Clark turns to Professor Fine, who convinces Clark that Jor-El is the one responsible for her illness and the only way to save her is to destroy the Fortress of Solitude. However, once the two arrive at the Fortress, Professor Fine tries to free Zod and kill Clark...

Lex is given an envelope with damaging information that could destroy Jonathan's life and must decide whether he will use it, as it will also bring harm to Clark and Martha. Before he can decide what to do, Lex is shot and falls into a coma. He dreams that his mother visits him and shows him the life he could lead if he walks away from his father and LuthorCorp. In this alternate life, Lex is happily married to Lana with a baby on the way. Meanwhile, Chloe asks Clark to use his powers to deliver Christmas presents to needy kids. When Clark meets a disgruntled Santa Claus who has lost all his Christmas glee...

Lex arranges a photo-op at the hospital, where he meets Samantha, the president of the Students for Lex Luthor club, who is more than a die-hard fan of his cause. Meanwhile Jonathan Kent starts to receive death threats from an anonymous source who demands he drops out of the race, while Martha Kent makes an unusual deal with Lionel Luthor...

After a bomb scare, Lex and Lana are trapped inside a mansion by two sadistic police officers named Greg and Harris, who want nothing more than the spaceship that crashed during the second meteor shower. Meanwhile the campaign between Lex and Jonathan goes neck and neck, and budget problems become an issue for the Kents...

In the 100th episode, Clark Kent confess to Lana his true identity; upon this, he takes her to the Fortress of Solitude and asks her to marry him. But as fate would have it, someone close to him will die. Can Clark change the outcome of events that are destined to occur, or will the outcome of death be inevitable? Meanwhile, the senatorial race heats up as the winner is determined.

Still struggling with the grief of his deceased father, Clark encounters a woman after his mother is mugged, named Andrea, in Metropolis who has similar powers to him which she obtained during the second meteor shower after a heart transplant. She has taken the role of a vigilante super hero, and is out to find out who murdered her mother a year earlier... Meanwhile a different side of Clark emerges because of the death of his father.

When Lois finds a corpse in the walls of The Talon, the spirit is released; Clark and Lois must now team up to find the killer. Who has murdered women around Smallville for the last ten years; after Lois is kidnapped it is up to Clark to rescue her before it is too late.

Victor Stone half-human and half-machine is released by a Doctor, we find out Victor was being experimented on by LuthorCorp. After Lana crashes her car into him, he appears to survive with out a scratch.. Lana confronts Clark who becomes friends with Victor and agrees to help Victor find his girlfriend Katherine. But Lex wants him back for his own personal agenda. Meanwhile Martha is black-mailed with a dvd video of Clark saving Lana.

Dr. Milton Fine aka Brainiac returns; this time deceiving Lex Luthor into helping him free General Zod. Using Lex's weakness of spaceships against him Lex accepts the terms... Meanwhile Clark is hypnotized by a young women wearing a crystal that can manipulate brainwaves into becoming her intimate item, only to try to persuade Clark into killing Lex Luthor.

Lana becomes addicted to a serum containing green kryptonite that allows her to to contact her deceased parents; as do Clark and Lex who are purposely injected with the serum which allows them to channel their late parents. Meanwhile, Lionel continues his efforts to get even closer to Martha Kent.

Clark befriends a second generation meteor victim, a girl who is able to control glass with her thoughts. After the girl's foster parent is murdered by telepathy with glass, Lois begins to suspect she may be a killer; but Clark believes otherwise. Meanwhile, the relationship between Lana and Lex steams up.

After Martha's life is put in harms way by a mad tormentor, only Lionel could save her after he is taking hostage by the masked-man. Lionel must win a series of elaborate games in order to survive. Meanwhile Clark confronts Martha about Lionel knowing his true secret, which was told to him by his late father Jonathan in the episode Void. Also Lex confronts Lana about intimacy that occurred.

Clark is not taking his break-up with Lana well, as she has now moved on with Lex. Clark then meets a man by the name of Graham Garrett whose life had been saved by Clark a little bit earlier. However Clark finds out that this new friend may be dangerous in more ways then one. Meanwhile Lois is given the job of Marthaa 's new Chief of Staff. Trailer

Clark is visited by whom he believes to be the ghost of his deceased father Jonathan Kent. This ghost then informs Clark to kill Lionel Luthor, which confuses Clark. Meanwhile Lex Luthor creates a vaccine for Finea 's deadly virus, but to Lexa ' dismay Fine intervenes and injects him with the vaccine. This causes an allergic chain reaction, with a shocking effect.

In Smallville's fifth-season finale, Clark's kryptonian origins threaten the Earth and the population, which Clark must make a huge sacrifice and a decisiona This decision will affect all of the citizens around him, affecting Lex, Lionel, Lana and Clark are set in motion, in the moment for which all his trials have prepared him for. Meanwhile Milton Fine unleashes a deadly virus that effects millions, and Lionel is again channeled by Jor-El who helps Clark (Kal-El) in the on sought battle between good and evil.