In London, a secret vigilante court uses a hangman's rope stolen from Scotland Yard's Black Museum to carry out its own death sentences on murderers who escaped justice, while a separate, unrelated killer is decapitating young women across the city — and the two cases become entangled as an inspector investigates. West German krimi (crime-thriller) loosely inspired by Edgar Wallace, notable for combining vigilante justice with a serial-killer plot in one film.