What in hell is going on at Headstone Manor? In this hilarious spoof of every horror fans favourite films, a team of mad scientists led by Dr. Lukas Mandeville (Kenny Everett) and his assistant Dr. Barbara Coyle (Pamela Stephenson) are investigating paranormal phenomenon in the mysterious manor. Unknown to the scientists, their presence is about to incur the wrath of a local coven of bumbling but determined Satanists led by a 700-year-old disciple of the Devil known only as the Sinister Man (Vincent Price), all of whom are prepared to stop at nothing in purging the house of the unwanted intruders.