A representative American middle-class family is stranded in a remote section of the southwest desert, where they’re cornered and attacked by their primitive counterparts—a cave-dwelling family of apparent mongoloids. This grisly 1977 thriller by Wes Craven attracted some attention for its thematic opposition of civilization and savagery, but the thesis doesn’t translate into a particularly effective movie, and Craven’s technique itself is too primitive to wring more than elementary chills from the material. 89 min.