Jack Bauer află despre o tentativă de asasinat asupra candidatului la președinție David Palmer.

Convingerea lui Jack că cineva de la CTU este implicat în complotul de asasinat provoacă fricțiuni.

Jack încearcă să obțină informații cheie de la Penticoff, iar Kimberly este predată lui Gaines.

Jack câștigă un avantaj în urmărirea unuia dintre asasini.

Kim se teme că mama ei a fost răpită din nou după ce sunt despărțite în timpul unei evadări.

Jack este forțat să lucreze cu un agent CTU prea zelos.

În timp ce Jack și Mason urmăresc o pistă, investigația lui Kim o trimite la închisoare.

Jack descoperă că de fapt câmpul gol găzduiește o închisoare guvernamentală subterană secretă.

Jack este la cheremul geniilor criminale pe care a încercat toată ziua să le captureze.

Jack este oferit în schimb pentru întoarcerea lui Alexis Drazen.

După o explozie, Jack sugerează relatarea morții lui Palmer pentru a câștiga avantaj.

Finalul plin de acțiune al sezonului îl găsește pe Jack în confruntarea supremă cu familia 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.