A doctor suspects that the new director of the psychiatric hospital where she works is an imposter, and that he is in reality a chronic amnesiac with a tendency to kill. But instead of turning him in to the police, she recklessly decides to unravel the truth about him herself. Alfred Hitchcock's psychological thriller, with Gregory Peck, Ingrid Bergman, Leo G Carroll, Michael Chekhov and Rhonda Fleming.

When Dr. Anthony Edwardes arrives at a Vermont mental hospital to replace the outgoing hospital director, Dr. Constance Peterson, a psychoanalyst, discovers Edwardes is actually an impostor. The man confesses that the real Dr. Edwardes is dead and fears he may have killed him, but cannot recall anything. Dr. Peterson, however is convinced his impostor is innocent of the man's murder, and joins him on a quest to unravel his amnesia through psychoanalysis.