David Palmer tells Sherry he wants a divorce. Conspiring with the Drazens, Nina tells Jack that Kim is dead. Jack kills Victor and Andre in cold blood. After learning that Kim is alive, Jack warns Mason that Nina must be the mole. George is skeptical but believes Jack after evidence shows that she killed Jamey. Nina is captured, but she has already killed Teri. Jack cradles his wife's lifeless body in anguish.
Jack and Michelle question Syed Ali, who claims that the audio recordings are false. Palmer prepares to wage war against the three countries who were involved in the nuclear strike. Kim gets caught in a hostage situation. Bauer is alerted to a conspiracy after Ali's assassination and is contacted by a man who wants to exchange information for Kate Warner.
President Palmer meets with Sherry, who agrees to help him with Milliken. Jack convinces Nina to work with him to get the virus from Amador. Hector wants to pull out of the deal.
After Air Force One is shot down by Mitch Anderson, CTU requests the help of two civilians who witnessed the crash. Mike Novick presses for the VP to be sworn in as President. Marwan and Jack both attempt to secure the nuclear football, a briefcase containing the launch codes for the entire US nuclear arsenal.
New discoveries regarding the day's horrific events keep Jack Bauer away from CTU, whose agenda Homeland Security has been ordered to reprioritize. Chloe O'Brian and Audrey Raines team together to assist with field operations and the investigation takes an unexpected turn.
Exposed to Starkwood's pathogen, Jack is examined by agents from the CDC and receives a grim prognosis. At the Starkwood compound, Tony escapes from enemy hands and enlists the aid of Jonas Hodges' assistant to put a stop to the bio-threat.
When it becomes clear that Kevin has no intention of upholding his end of the bargain, Dana Walsh prepares to take drastic action. Kayla Hassan attempts to intervene against her father on Tarin's behalf. Jack Bauer brings Sergei Bazhaev into custody, but an unforeseen betrayal derails the operation, placing the nuclear rods back in enemy hands.