A new director, the famous scientist Edwards, arrives at the Institute of Psychiatry. An employee of the institute, Constance Petersen, shows not only a professional interest in him, and they start a whirlwind love affair. But the young professor begins to behave very strangely, and soon Constance discovers that her lover is not who he claims to be - he is an impostor suffering from amnesia. His real name is John Ballantyne, and everything points to the fact that he was a patient of the missing Dr. Edwards and may be the killer. Not believing that John is a criminal, Constance takes him to her old teacher Dr. Bryulov. They hope, by studying Johns dreams, to reveal the secrets hidden in the depths of his consciousness.