Four friends are attacked by a demon while on a picnic, due to possession of a tome of mystic information. Told in flashbacks by the sole survivor.
Four teenagers go on a woods hike and encounter a creepy forest ranger and a crazy old man. The old man is a scientist who had found a mysterious book bound in human skin, the Necronomicon, and when he had read its cryptic symbols it conjured monsters into existence. The teenagers keep the book, and are then persued by monsters, a demonic cult, and the ranger. The ranger turns out to be a red flying devil in human disguise.
- The movie begins with a reporter going to a local asylum to interview a strange inmate who has been there for a year. David Fielding (Edward Connell) has been in an institution since he ran from the woods leaving behind his girl friend Susan Turner (Barbara Hewitt) and two others, good buddy Jim (Frank Bonner) and his girl friend Vicki (Robin Christopher) after their picnic gone bad and he retells the tale to the reporter. When they arrive at the State Park they discover a cave with maniacal laughter emanating from it and upon investigating discover an old man who gives them a large book containing ancient hieroglyphics and other indecipherable symbols. As they attempt to translate the writing in the book a Forest Ranger comes along but in reality the man is an ancient evil god named Asmodeus (Jack Woods) who is after the book and will do whatever it takes to retrieve it. Asmodeus is driven to have his way with Susan and Vicki and sends forth a variety of evil monsters bent on retrieving the magical book from the teens. As the action builds to a climax David finds that he is the only one who is able to reason what is happening to the group and musters all his powers to overcome the metaphysical powers of Asmodeus.