The ranks of a Satan-worshiping biker gang known as the Grave Diggers are being thinned out by a mysterious assailant. Enter Stone (Ken Shorter), an undercover cop who's just hairy and bedraggled enough to pass for one of the hell-raisers. Exploitation thrills come at full throttle in this infamous Australian outing. Director/co-writer Sandy Harbutt, Hugh Keays-Byrne also star. 99 min. Widescreen (Enhanced); Soundtrack: English Dolby Digital mono; behind-the-scenes footage; documentaries; photo gallery; theatrical trailer. Two-disc set.