If their city has been rocked by a string of brutal occult murders, veteran detective John Locke and his young partner Terri Keyes have been made to put their differences aside and abide by the trail of evidence to some formerly abandoned asylum, where the new owner doctor Unnseine is running his own new Nazi-inspired"medical research" on the unwilling inmates. The sexy but deadly Annie Dyer, one particular inmate, may contain the key to the murders - and also to the door to Hell itself - if merely Keyes and Locke can stay alive long enough to detect exactly what it is.