Itinerant magician Balzamo arrives in the town where Dr. Emerson and his pretty young wife live. Smitten with Mrs. Emerson, Balzamo places her under a hypnotic spell and takes her away with him. Many years later, as she lies near death, she warns her daughter Dorothy to flee from the evil Balzamo. Dorothy runs away to a small town and stays with Mrs. Arnold and her son John, but when she and John become engaged, Dorothy suddenly begins acting strangely, changing her personality and even her name. She is taken to the sanatorium of a specialist in nerve disorders--who turns out to be none other than Dr. Emerson, the man whose wife was Dorothy's mother. Complications ensue.