Dinah St. Clair is the daughter of a successful record producer. An old acquaintance shows up at their high-rise penthouse and for old times sake Dinah lets him in. She has no idea that Joe has just escaped from a mental ward and is beset by homicidal impulses that he cannot control. Joe makes Dinah his hostage and while her father and the police are coming up with a plan to rescue her, she is desperately trying to save herself and Joe.