While Jack has problems with Curtis, CTU discovers a nuclear threat and raids a terrorist warehouse, and a shocking explosion shakes LA.

Jack looks for a Russian national as his father plots with shadowy patriots. Meanwhile, the President and the Constitution may be in danger.

Jack's search takes him to the home of an old enemy, while a bomber slips into the White House.

Jack baits Fayed with Gredenko, while the President faces a challenge to his office.

A missing computer circuit board: the Russians get wind of Chinese espionage, the White House must find a leak, and CTU interrogates an unlikely witness.

Russia presses the White House, while Jack must try to thwart the Chinese and his oldest antagonist simultaneously.