After watching this movie you can't help but realize how much the directors of THE BLAIR WITCH PROJECT and THE EVIL DEAD owe to this movie. Two couples, who are supposed to meet up with their archeology professor in the woods, encounter some strange goings on....they come across the Professor's cabin to find it destroyed, they see strange giant footprints on the ground-and are given an old, leatherbound book containing satanic spells by a crazy old guy who lives in a cave. Through the Professor's journal they are informed that some of those spells in the book worked-and that he summoned some creatures from hell, among them a large stop-motion ape creature and a sinister character named Asmodeus. Only one of the students escapes the creatures-only to be committed to the mental wing of a hospital, where his story is told in flashback.