At the end of the fifth season, Jack (Kiefer Sutherland) was unexpectedly secretly arrested by China and was detained for 20 months. Jack endured inhuman torture but did not say a word. At this time, the United States was threatened by terrorist bomb attacks, and evidence showed that it might be the work of Islamic armed groups. CTU investigation found that the mastermind behind this series of terrorist attacks was an Islamic terrorist named Assad. In order to successfully implement the assassination plan against Assad, the United States negotiated with China and exchanged for the imprisoned Jack Bauer. It was intended to use Jack as bait to lure out Assad. However, in a series of activities to lure Assad to appear, Jack discovered that there was someone else behind the terrorist attack. In order to defuse the impending terrorist attack, Jack once again stepped forward and fought against the terrorists alone...