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.

Kimberly and Janet realize they are in danger after it becomes clear that their two dates have kidnapped them. Despite the threat on his life, Senator Palmer sneaks out of his hotel to meet a reporter who has damaging information that could affect his campaign. Back at the office, Jack has Jamey, a member of his team, decrypt the key card.

Convinced Jack needs to be relieved of his command, one of his team members, Tony, calls George Mason who arrives and puts the CTU under lock-down. With the help of his second-in-command, Nina, Jack slips out and heads for an address listed on the key card. Once there he encounters a shooter who hints that Kimberly's disappearance is part of a bigger plan. Meanwhile, the two boys deliver Kimberly to a man named Ira Gaines.

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.

Now, under constant surveillance from Gaines, Jack goes back to CTU where Nina inadvertently gets in the way of Gains' plan. Teri tries to escape from York, but her call to CTU only brings more help for York. Meanwhile, Palmer tries to convince his family that they need to tell the press about a secret personal tragedy from their past before it's too late.

In order to save his wife and daughter, Jack is ordered to deliver a briefcase to a man at Senator Palmer's rally. Realizing this man must be the assassin, Jack struggles to find a way to protect both Palmer and his family. Back at the CTU, Nina and Tony think they have found the traitor within the midst.

Although he prevents Palmer's assassination, Jack is taken into custody where his story of his kidnapped wife and daughter is not believed. Knowing his family will only be kept alive if he is free to help Gaines, Jack knows he must escape. Back at Gaines' compound, Teri and Kimberly struggle to stay alive, while at CTU the traitor reveals that the whole unit has been wired so Gaines can watch their every move.

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.

Jack learns that one of the assassins, Alexis Mecir, is actually Victor Drazen's son and has become intimate with one of Palmer's aides. In an attempt to find the man ordering the assassinations, the aide agrees to plant a tracking device in Alexis' wallet. Back at the safe house, Teri and Kim discover their location is no longer secret or safe.

During their escape from the safe house Teri and Kim become separated, and the traumatic events of the day result in Teri passing out and then awakening with amnesia. Assuming her mother has been re-kidnapped, Kim conducts her own search for information concerning her mother's abductors. When the plan to track Alexis backfires, Jack pretends to be Alexis in order to keep a rendezvous with one of Alexis' contacts.

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.

Alexis' contact turns out to be a power company worker who was being paid to shut off the electricity to a power grid out in the middle of an empty field. As Jack and Mason follow up on that lead, Kim's search for information lands her in jail, even as Palmer's press conference disclosure could ultimately put his own son in jail.

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.