In the previous season, in order to get rid of the vendetta, Jack (Kiefer Sutherland) used a trick to escape and lived an ordinary life incognito. However, with the former President David Ballmer (Dennis Haysbert), former colleagues Michelle (Reiko Aylesworth) and Tony (Carlos Bernard) being killed one after another, Chloe (Mary Lynn Rajskub), the last colleague who knew Jack was still alive, was also threatened with death. As a last resort, Chloe called Jack to ask him for help. When Chloe and Jack met, the killer appeared, and Jack finally caught the person who was chasing them with an extraordinary hand. And forced him to ask that the assassination of the former president was their main task, and the other goals were just to point the investigation at Jack, making Jack the scapegoat for this assassination mission. The purpose of killing the former president was to silence him and prevent him from revealing certain things. So what did the former president want to say? Jack had to abandon his current ordinary life and was once again involved in a shocking conspiracy.