A psychologist (Crenna) and his wife (Pettet) rent a haunted house for use as a drug-rehabilitation center. When strange things start to happen, they invite a group of students to help investigate. A trapdoor discovered in the cellar exudes a nasty force that engulfs and disposes of them
all one by one. The film is expertly done; director Trikonis knows how to make a haunted house movie. Buono is sublime as the Devil himself, although his final scene has been cut out of some prints.