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.

Jack rushes to the aid of CTU Director Richard Walsh who comes into possession of a keycard and ends up in a shootout. Gaines encounters trouble acquiring Martin Belkin's ID from Mandy. Elsewhere, Kim realises the gravity of her situation.

As Kim and Janet temporarily escape their captors, Senator Palmer learns that his son may have been involved in the death of his daughter's rapist 7 years ago. Gaines finally gets Belkin's ID from Mandy, while Jack delivers the keycard to CTU.

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.

Jack meets up with Teri at the hospital where they wait to talk to Janet about Kim. However, Janet is killed by Alan who is really working for Ira Gaines. Palmer confronts his family about the cover up. The body of the real Alan York is found near CTU by Nina Meyers.

Jack returns to CTU to switch out the id card with a fake per Gaines' orders. Palmer tries to convince Keith and Sherry to go public about the murder.

Jack is taken into custody by the Secret Service after he stops the assassination. He quickly escapes in order to check on another name from the key card. Palmer tries to deal with the assassination attempt.

Jack is on the run after escaping custody and rushes to intercept Ted Cofell before he leaves the city. Nina receives a phone call from Teri and tries to trace the call. Palmer still wants to go ahead with the press conference despite objections. Alberta Green temporarily takes over as Director of CTU.

Jack takes Ted Cofell hostage after finding his name on the key-card and tries to get whatever info he has about the conspiracy which only amounts to the name of another conspirator, a one Kevin Carroll. Palmer starts to piece together his connection to Jack. Gaines receives orders to kill Teri and Kim from his boss Andre Drazen.

Kevin Carroll (the man who pretended to be York) leads Jack to Gaines' compound where he is quickly discovered. Nina and Tony try work around Director's Green's strict new protocols to help Jack. Palmer discovers that Carl Webb, one of his financiers is handling the Keith situation his own way.

Jack has a final confrontation with Gaines as a CTU chopper heads to the compound. Nina and Tony talk to Jamey's mother in order to learn why she was helping the assassins. Carl Webb threatens Palmer to keep quiet about the murder once and for all. CTU learns that more assassins are on their way to LA.

Director Green and Regional Director Ryan Chappelle question Jack about the day's events. Nina takes Kim and Teri to a safe house after getting them medical attention. Palmer wants a meeting with Jack.

Palmer and Jack finally meet for the first time and discuss Operation Nightfall. Nina talks to Teri about her and Jack's past relationship after they reach the safehouse.

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.