Cult Australian biker film made in the 1970s. After one of their number witnesses the assassination of a leading ecological campaigner, members of the outlaw biker gang the Gravediggers Motorcycle Club - led by The Undertaker (Sandy Harbutt) - start getting killed off one by one. When undercover cop Stone (Ken Shorter) infiltrates the group in an attempt to track down the murderer, he manages to gain some hard-earned credibility with the bikers, and even some respect.