Dr. Petersen notices that there is something strange about Dr. Edwardes. He has a peculiar phobia about seeing sets of parallel lines against a white background, first displayed in an inappropriate reaction to seeing a diagram drawn with the tines of a fork on a tablecloth. Dr. Petersen soon realizes, by comparing handwriting, that this man is an impostor and not the real Dr. Edwardes. He confides to her that he killed Dr. Edwardes and took his place. He suffers from massive amnesia and does not know who he is. ‘Dr. Edwardes’ disappears during the night, having left a note for Dr. Petersen that he is going to New York City. It becomes public knowledge that ‘Dr. Edwardes’ is an impostor, and that the real Dr. Edwardes is missing and may have been murdered. Dr. Petersen goes to the hotel indicated in the note, knowing that the police are in pursuit. She needs to use her psychoanalytic skills to unlock his amnesia and find out what had really happened. One of Hitchcock’s characteristic innocent-person-pursued-by-the-police evasions ensues, as Dr. Petersen and the impostor (who now calls himself ‘John Brown’) travel by train to Rochester, to meet Dr. Brulov (Michael Chekhov), who had been Dr. Petersen’s teacher and mentor. The two doctors analyze a dream that ‘John Brown’ had. The dream sequence (designed by Salvador Dalí) is full of psychoanalytic symbols—eyes, curtains, scissors, playing cards (some of them blank), a man with no face, a man falling off a building, a man hiding behind a chimney dropping a wheel and wings. They deduce that Brown and Edwardes had been on a ski trip together (the lines in white are ski tracks) and that Edwardes had somehow died there. Dr. Petersen and Brown go to the ski resort (the wings provide a clue) to reenact the event and unlock his repressed memories. Near the bottom of the hill, Brown’s memory suddenly returns. He recalls that there is a precipice in front of them, over which Edwardes had fallen to his death. He stops them just in time. He also remembers a traumatic event from his childhood—he slid down some stairs and accidentally knocked his brother onto sharp pointed railings, killing him. This incident had caused him to develop amnesia and a generalized guilt complex. He also remembers that his real name is John Ballantine. All is understood now, and Ballantine is about to be exonerated, when it is discovered that Edwardes had a bullet in his body. Ballantine is convicted of murder and sent to prison. A heartbroken Dr. Petersen returns to her position at the hospital, where Dr. Murchison is once again the director. After reconsidering her notes from the dream, she realizes that the ‘wheel’ was a revolver and that the man hiding behind the chimney and dropping the wheel was Dr. Murchison hiding behind a tree, shooting Dr. Edwardes and dropping the gun. She confronts Murchison with this and he confesses, but says that he didn’t drop the gun; he still has it. He pulls it out of his desk and threatens to shoot her. However, when she points out that while the first murder carried extenuating circumstances of his own mental state, murdering her as well surely would result in the electric chair, the man chooses instead to kill himself. Dr. Petersen is then reunited with Ballantine.