The kind but physically disfigured Dr. Heckyl (Oliver Reed) is so distraught over his continual failures with the opposite sex that he decides to end his life by overdosing on an extra-strength diet drink. Strangely, he doesn't die -- he transforms into slick stud Mr. Hype. Unfortunately, Hype has an insatiable thirst for blood, and he ends up killing his dates before any romance unfolds. He soon sets his sights on the sweet Coral (Sunny Johnson), who secretly loves Heckyl, but not Hype.