Fresh from the Korean War, Bennett Marco (Frank Sinatra) wants nothing more than to return to peaceful civilian life. However, his dreams are shattered both figuratively and literally when he finds himself suffering from horrible, yet unusual recurring nightmares of he and a group of U. S. soldiers being captured and brainwashed by Communists. Although all indications point to post traumatic stress syndrome, Marco is suspicious that something else is afoot, as he not only notices that he and other veterans have had the same dream, but that they all seem to unthinkingly recite the same line of praise and affection for Raymond Shaw (Laurence Harvey), a war hero but antisocial snob who they had all despised in combat. As he investigates Harvey and his family, the bumbling Senator John Yerkes Iselin (James Gregory) and his wife (Angela Lansbury), Raymond unveils a shocking conspiracy that could upset democracy in the balance and turn the Cold War in favor of the Communists.