In 1944, Nazi agent Erich Gimpel is summoned by a German general staff that knows it is about to lose the war. This loyal officer is given a last chance mission: to go to the United States to spy on the progress of American research on the atomic bomb and try to hinder its completion. To assist him, he is joined by Billy Cole, an American deserter ready to collaborate. While the two men are landed by a submarine on the New York coast, Cole, an alcoholic, quickly proves to be uncontrollable.