Now confined to a mental hospital, young Kirsty insists her supposedly dead father is actually stuck in Hell following his wife’s betrayal. Few believe the young woman’s lurid stories aside from the thrill-seeking Dr. Channard. Kirsty is undeterred and, with the help of a fellow patient, heads to Hell for a rescue.

A spate of killings of teenagers by a maniac dressed like a hippie causes a detective to check the records for similar killings. He discovers that every five years, in the fifth month of the year, for five consecutive days, the same type of killings have occurred, and the few descriptions of the suspect always match: he's dressed like a hippie. As the detective searches for the killer, he begins to have suspicions about his superior, an older man who is haunted by memories of his military service in Vietnam.