Major Bennett Marco (Denzel Washington) and Sergeant Raymond Shaw (Liev Schreiber), with the other members of their platoon, are captured during the Korean War in 1952. Their captors brainwash them into believing that Shaw saved their lives. Upon returning to the US, Shaw receives a medal for courage. After the war, Marco starts dreaming about Shaw killing two members of their platoon. He meets a war comrade and learns that the latter has had the very same dream. Marco decides to investigate. It turns out that Shaw is a sleeping agent, conditioned to “wake up” when he sees a queen of diamonds from a deck of playing cards. And Shaw’s master, the person who controls him when he’s under the spell of the queen of diamonds, is none other than his own mother Eleanor Shaw (Meryl Streep), a Senator who is also working with Communists in a plot to overthrow the US government. In the meantime, Shaw has become a congressman and is struggling with Senator Tom Jordan (Jon Voight) to be nominated as a vice-presidential candidate. With everyone doubting his sanity, Marco races to unveil the truth and save his country.