Dr. Basil Willing tackles the case of a doppleganger involved in murder, and meets his future wife in the bargain.
From the Dell paperback edition: "Strange, evil happenings and an aura of impending doom weigh heavily on a beautiful girl who is the unfortunate victim of a terror-filled existence. The bizarre events are seemingly supernatural to all persons but Dr. Basil Willing. He follows a murderer's trail through the worlds of spirit and legend and back into this world to solve the case of the only woman who could never have an alibi."