In 1950, Maj. Jefferson Pike, an Army intelligence agent who served with distinction in World War II, awakens in a hospital with severe amnesia. He isn't sure where he is, how he got there, or even who the woman at his side is, even though the doctor tells him that her name is Anna and that she is his wife. The doctor instructs Pike to recall, in as much detail as possible, what he was doing before the accident that caused his traumatic memory loss. But the doctor isn't a doctor, Anna isn't Pike's wife, it isn't 1950, and he isn't in an American hospital. World War II is still very much in progress, and Pike is being duped in an elaborate scheme prepared by Maj. Walter Gerber (Rod Taylor), a German intelligence agent. Gerber is trying to trick a drugged and suggestible Pike into telling him everything he knows, as the injured soldier lies in a Bavarian military hospital after being taken prisoner. The longer his stay last, the more he becomes suspicious of his surroundings.