Confined to a mental hospital, young Kirsty Cotton insists her supposedly dead father is stuck in hell, controlled by sadomasochistic demons after being betrayed by his evil, occult-obsessed wife, Julia. Few believe Kirsty, except the thrill-seeking Dr. Channard, who is intrigued by the young woman's lurid stories. So when Kirsty and fellow patient Tiffany head to hell for a rescue, Channard and Julia are close behind.
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.
