On holiday in the Bahamas, Frances Ogilvie meets a strangely attractive man whom she allows to hypnotize her, she supposes as a party trick. But on her return to England she realizes that he has not removed the spell, that she is still under his control. Her efforts to free herself collapse when her master comes to England to find her, and she plunges into a nightmare world of coercion and murder. While knowing what is happening around her, she can do nothing to prevent events until at last she manages to unlock the secret of his power and bring his career to a dramatic end.