Counter Terrorist Unit agent Jack Bauer is assigned to protect presidential candidate David Palmer from a potential assassination attempt. Unfortunately, his daughter has disappeared and someone within CTU may be involved. Mandy seduces Martin Belkin, a photographer headed for a meeting with the Senator.

District Director George Mason (Berkely) shuts down CTU forcing Jack to escape in order to follow up on a lead on a conspirator. Nina and Jamie try to cover for him. Palmer discovers how a reporter found out about Keith. Jack finally learns that Kim and Janet have been kidnapped.

Jack follows the arrested conspirator to the police station in order to get more info on Kim's whereabouts. Palmer meets with a reporter who has some damaging information. Kim realizes just how dangerous Ira Gaines really is.

After handing out photos of all the assassins, Jack and Mason discover that one of Palmer's campaign staff is in a romantic relationship with Alexis Drazen. Teri and Kim are attacked in the safehouse. Keith confronts Carl Webb about the cover-up.

Jack and Mason use Palmer's campaign staffer Elizabeth Nash in a sting against Alexis Drazen which backfires badly on them. Kim makes a run for Rick's house after getting separated from Teri following the attack.

Jack poses as Alexis Drazen and goes to meet a contact who has vital information. However, a CTU agent with a grudge against Jack might risk the success of the mission. Dr. Parslow takes Teri back to the Bauer house.

Jack and Mason search for location of the address found in Victor Drazen's confidential file. Palmer finally lets the press know about Keith's past. One of Drazen's goons closes in on Teri; Kim is arrested after the police raid Rick's house.

Jack discovers a top secret detention center houses someone from his past. Tony takes Teri back to CTU as Kim finds herself in jail. Andre Drazen and his soldiers raid the detention center.

Jack is captured by Victor Drazen and Andre when they escape the detention center. Palmer learns he is dominating the California polls. Drazen's men capture Kim after she is released from jail.

In order to buy himself more time Jack puts Victor and Andre in contact via Mason with a hospitalized Alexis Drazen. Palmer becomes involved with a campaign staffer. Tony and Nina learn that Kim has been recaptured.

Jack delivers a cell phone that is unknowingly rigged to explode to Palmer. Kim manages to escape. The identity of the real mole inside CTU is exposed.

Jack Bauer heads to the docks for a final climactic showdown with Victor Drazen.

It's been a year since Jack lost his wife, and the emotional toll includes estrangement from his daughter Kim, who is now a live-in au pair for a troubled family. Jack is no longer with CTU, and no longer interested in that line of work - until he's summoned directly by President Palmer. The situation: terrorists have planted a nuclear device somewhere in Los Angeles and plan to detonate it within 24 hours.

Jack reestablishes his undercover identity to join a crew of suspected terrorists that may know something about the nuclear device planted in Los Angeles. Posing as career criminal Jack Roush, his only hope in proving his loyalty to them lies in the package he's carrying. Meanwhile, President Palmer deals with a curious press, including one particularly skeptical reporter; Kim tries to protect Megan from her father; and Kate Warner follows up on suspicions about her sister's fiancé.

Jack tries to undermine Eddie's mission to bomb CTU while George investigates intel leading him to the site of the nuclear bomb's construction and Kim tries to make contact with her father by heading for CTU headquarters.

George returns to CTU where he orders the medics to revive a badly injured Paula, who has vital information. Palmer comes down hard on Eric for his deception. Kim takes Megan to the hospital, but the staff accuses her of abuse. Jack locates the leader of the American terrorist cell. He learns that the woman who gave them inside information on CTU is an old enemy.

George refuses to allow Jack to assist in Nina's interrogation. Jack resorts to blackmail to change George's mind. Palmer and Stanton meet with a Middle Eastern ambassador who may be in league with Second Wave. Tony visits the Warner home and questions Reza about his possible connection with Syed Ali.

Jack begins his interrogation of Nina and pushes all boundaries in order to force her to divulge the name of her contact. Palmer is surprised and suspicious when his ex wife Sherry returns and claims to have information about a conspiracy against him from within his own administration. Kim and Miguel plan to kidnap Megan from the hospital in order to take her out of LA and away from the nuclear threat.

Jack forces Nina to help with a sting operation against her contact in the hopes that he can lead them to the bomb. Palmer and Mike try to gage Stanton's loyalty when they investigate the chopper crash. George has a final conversation with his son.

Kim and Miguel are arrested and the police plan to take them back to LA. Tony questions Bob Warner at CTU and learns more about his government connections. Palmer discovers a traitor in his ranks when the journalist whom he was holding is set free. Nina pulls a deadly countermove, setting herself up as the main player in the search to locate the bomb.

George pits Bob against Reza in hopes of learning which one is working with Second Wave. Sherry and Lynne clash over Palmer's speech to the press. Kate is interrogated by Syed Ali, who believes she knows too much about the bomb. Jack and Nina fight off a group of renegade soldiers while waiting to be rescued from the crash site. They nearly escape when Nina takes Jack hostage and demands to speak to the President.

Two traitors are uncovered. One is the mole in the Palmer administration who is working with Stanton. The other is the member of the Warner family who helped Syed Ali to bring the bomb into the country. Jack learns of Ali's location and tries to rescue Kate. Kim and Miguel hatch an escape plan to stay out of LA, but the results are disastrous.

Kate helps Jack to locate and identify Syed Ali. Palmer places Stanton under arrest, but he won't break. Palmer realizes he must go to extremes to make Stanton talk. Kim hits her low point of the day when she encounters a cougar in the woods.

Jack engages in a brutal contest of wills with Syed Ali. George questions Bob Warner to learn more about Marie's motivations for helping the terrorists. Kim is rescued by a mysterious hunter who offers her asylum. Lynne receives a dire warning from Sherry.

Jack and his men prepare for a confrontation with Stanton's renegade soldiers as they converge on the bomb. Kim becomes suspicious of her host, but is forced to stay because of her status with the police. Stanton finally breaks down and gives Palmer some unpleasant news.

Jack and Kate try to break Marie's resolve so they can learn the location of the bomb. Palmer confronts his ex wife with the information that Stanton gave them. George finally steps down as director of CTU and hands the position over to Tony. Kim discovers her host's deception.

Palmer, Mike and Lynne discuss various ways to dispose of the ticking bomb. They conclude that the desert is the best place to set it off. Jack determines that one man must pilot the plane carrying the bomb. He chooses to fly the plane himself and bids a tearful goodbye to his daughter. Tony and Michelle become suspicious of a Middle Eastern diplomat who is asking questions about the evidence against Syed Ali. Palmer departs for Los Angeles so he can be on hand when news of the nuclear bomb reaches the public.