Summary:Its 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 hes 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.

Summary: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 hes 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 sisters fiance.

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

Summary:Mason faces a no-win situation, while his attempts to retrieve vital information may cost other lives; Reza joins Kate on an errand; Tony and Michelle deal with the aftermath of the CTU bombing; Kim tries to talk Carla into taking a stand for Megan; Jack faces off with Joseph Wald to learn who gave the order to bomb CTU.

Summary:George refuses to allow Jack to assist in Ninas interrogation. Jack resorts to blackmail to change Georges 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.

Summary:Nina tries to set the rules as Jack begins his interrogation of the woman who betrayed CTU and killed his wife; the president - dealing with the aftermath of another tragedy - tries to curb speculation by the media and learns from a surprisingly informed source that one of his orders has been countermanded; Marie hurls accusations at her sister Kate as Tony continues to question Reza; Miguel tries to distract Gary at the hospital; and Kim reaches Megan.

Summary:Finesse rather than force is required once Jack and Nina reach Visalia; Palmer directs his Chief of Staff to investigate Sherrys charge that a conspiracy within his own government is trying to undermine him; Mason contacts his estranged son; Warner and Reza are taken to CTU.

Summary:While Nina and Faheen are brought together, Jack and Michelle must try and decipher their conversation in Arabic for any clue to where the bomb is located; Kim and Miguel are questioned by the police for details about a grizzly discovery in the trunk of Garys car; and Tony interrogates Reza and Bob, who contradict each other about their possible terrorist ties; Palmer deals with an information leak; and the crew transporting the nuclear device encounters trouble.

Summary:Jack and Ninas plane crashes; Tony discovers Masons secret; Mason pits Reza against Bob to discover which of them has ties to the terrorist; Palmer thinks about out how to deal with Weilands news broadcast.

Summary:Palmer helps Jack get away from Nina; Jack learns the commandos who attacked him may have been sent by the NSA; Kim and Miguel try to get away from the police; Mason sinks into nostalgia as his time grows short; Reza helps CTU agents search Bobs computer files.

Summary:Jack utilizes Kates unique knowledge to track Syed Ali; Palmer goes to an extreme to extract information from Stanton about the bomb; Kim eludes the California State Police and faces a new and unexpected enemy; Sherry tries to play Stantons arrest to earn the Presidents trust; Tony continues the interrogation of Robert Warner.

Summary:Robert Warner gives some history on Marie, who talks to Kate; Jack explores a suspects vulnerability; Mason tells Tony to stop searching for Kim; Lynne investigates a suspicion about Sherry.

Summary:Jack organizes an assault on the paramilitary unit Corral Snake at Norton Airfield Base; Kim becomes acclimated to her new environs when a hunter finds her with an ankle injury; Roger Stanton cracks under the pressure of Ted Simmons interrogation; a CTU Division agent tries to evaluate the Counter-Terrorism Units capabilities; Palmer utilizes Sherrys connections to investigate a lead.

Summary:Jack learns the plane supposedly transporting the bomb is a decoy; Palmer confronts Sherry with information obtained from Roger Stanton; CTU initiates a search for the seventh commando of the Corral Snake unit; Kate aids in the interrogation of a suspect; Kim is led to believe that the nuclear bomb has detonated; George Mason steps down, assigning Tony Almeida the new Director of CTU.

Summary:A detonation deadline is established for the nuclear bomb; Palmers staff considers two courses of action for the bombs disposal; Kim leaves Lonnie McRaes cabin to head for San Jose and contacts her father; Jack volunteers for a disposal mission from which he may not return; Mason makes one last bid to die a hero; Palmer and Mike Novick board Air Force One for Los Angeles; Tony and the CTU staff analyze personal effects from Syed Alis safehouse.

Summary:Syed Ali denies that the recordings retrieved from his safehouse are authentic; Palmer preps a major military action against the three suspect nations; Sniper-fire interrupts Alis transfer to Guantanamo; Suspicion over the recordings spark tensions between Jack and Tony; Palmer affords Jack a matter of hours to provide proof of Alis statements; Kim walks into a desperate hostage situation; Jack is contacted by the surviving member of Corral Snake with an odd demand.

Summary:Jack receives a surprising ally before meeting with the surviving member of Coral Snake, who explains the purpose behind the bomb; the Vice President expresses concern about Palmers capability; Carrie shares her suspicions about Michelle with Tony; Kim balances a precarious hostage situation.

Summary:Jack, Kate, Yusef and Captain Wallace fight their way out of a surprise siege; Kim turns herself over to the police and is re-united with Miguel; President Palmer handles East Coast riots with National Guard response; tensions continue between Carrie and Michelle, with Tony refereeing the catfighting; Jack locates the evidence that proves the Cypress Recordings were falsified.

Summary:Jacks resolve is tested by a bomber hoping to keep his plan intact; Tony meets the source of stress between Carrie and Michelle; a presidential advisors loyalty is questioned.

Summary:Jack is revived, but not without ill effect; Kingsley demands the whereabouts of the Cypress Chip; Mike Novick goes to extreme measures to keep Lynne Kresge quiet; Kate makes a bargain with Yusefs assailants to protect the Cypress Chip; Tony and Michelle face pressure from Ryan Chappelle and Carrie at CTU.

Summary:Jack rescues Kate and retrieves the Cypress Chip; tensions escalate in the CTU between those still supporting Jacks mission, and those trying to stop it; Palmer faces a Cabinet tribunal demanding his resignation; Kim is released from police custody; Jack follows the only useful lead obtained from the damaged Cypress Chip.

Summary:Backdoor dealings, back stabbings and an actual stabbing convolute matters in this piercing hour, as Jack comes face-to-face with a pair of key players. One can prove the Cyprus recording is a fake; the other knows enough to blow the entire case wide open. But both begin to question their mutual trust when Jack tries to play each against the other. Meanwhile, a shakedown at CTU puts Jacks quest to rest once staffers are informed of a major shake-up in DC; Tony learns he has something in common with Palmer, who lobbies for an ally and talks with a turncoat; and Jack encourages Kim to put a definitive end to the source of her problems.

Summary:Chappelles unavailability prompts Division to question Tony, who puts Michelle in position to circumvent their command; Palmer is asked to perform a final executive action; Jack proposes a deal between conspirators.

Summary:Jack and Sherry Palmer prepare for a dangerous meeting with the head of the war conspiracy at the L.A. Coliseum; David Palmer sits in as the Cabinet waits for confirmation of the Cypress Chips invalidity; the air strike on the Middle East draws nearer; the conspiracy goes to an old agent to put Palmer out of play.