Moments after discovering his daughter, Kimberly, has snuck out of the house, Jack Bauer is called into work. As head of the CIA's Los Angeles Counter Terrorist Unit office he's told that an assassination attempt will be made within the next 24 hours on the life of presidential candidate David Palmer and it's up to his team of agents to keep Palmer alive. Meanwhile, Jack's wife, Teri, sets out to find their daughter.

Teri receives a phone call from Alan York who says his daughter, Janet, is a friend of Kimberly's and is also missing, so the two parents join forces to try and find the girls. Even as Jack is secretly called out of the office and given an encrypted key card containing information on the Palmer hit that could lead him to a dirty agent within his organization, the explosion of a 747 over the Mojave Desert becomes yet another piece in the puzzle.

Jack follows the arrested shooter to the police station in hopes of interrogating him only to find that Mason has arrived and taken control of the situation. But when the shooter says he will talk only to Jack, Jack learns he must break the shooter out of jail in order to learn who has kidnapped Kimberly. Back at the hotel, Senator Palmer learns more about the threatened news leak that could hurt his campaign.

While Jack is questioned at the CTU, Teri and Kim are taken to the clinic to be examined. Meanwhile, certain he recognizes the name Jack Bauer, Palmer has Jack's background investigated. When he discovers that Jack was the sole survivor of a secret mission that he authorized two years ago, Palmer becomes convinced Jack is out for revenge and insists on talking to Jack face to face.

Against his family's wishes, Senator Palmer decides to go public about the secret scandal surrounding his family. Even as Alexis' brother, Andre, sends another assassin to the Bauer residence in hopes of finding Teri and Kim, a confused and scared Teri meets Dr. Parslow, a man who says they are good friends. Unaware of the danger Teri is in, he offers to give her a ride home.

As Kim tries to get the police to call CTU, Jack discovers that the empty field where the power grid is located actually houses a secret underground government prison and that night's scheduled arrival is none other than Victor Drazen, the man Jack supposedly killed two years ago. Now Jack's convinced Victor's sons are coming to break him out.

Jack's fears are proven true when Andre Drazen breaks into the underground facility to rescue his father. With Jack as his prisoner Victor calls CTU, but Mason tells him he doesn't negotiate with terrorists. Desperate to buy some time, Jack tells Victor that his son, Alexis, is still alive. Back at the police station the police finally let Kim go, but her drive to CTU doesn't go as planned.

Jack has Nina connect Victor Drazen to a hospital phone so he can talk directly to Alexis. Nina then advises Palmer of the situation. Palmer urges Mason to arrange the exchange Drazen proposed: the return of Jack for the return of Alexis. Although Alexis is delivered, Drazen holds onto Kim and tells Jack he needs to do one last thing if he wants to see his daughter again.

Jack arrives at Palmer's hotel with a phone on which Drazen will call and ask Palmer to unfreeze $200,000,000 of his assets. When Palmer tells Jack that Drazen knows that's impossible, Jack grabs the phone and throws it off the balcony. It explodes seconds later. Realizing Drazen will never give up, Jack suggests having the television report that Palmer died in the explosion, leaving Jack to offer himself up in exchange for Kim.