该片讲述了一个牧羊少年因目睹一起杀人案，竟被人推下悬崖。一个平民在孤独的抗议，被当街射杀，尸体在流血，无人问津。正直的警察局长蓬纳维亚早就对法律的公正丧失信心，雇凶不成，就自己充当杀手，干掉了这一切罪恶的幕后黑手——一个名义上的地产承包商罗蒙诺。而自己在自首后，被买通的犯人在狱中杀害。One of the first films about the mafia occurrence, in which the fight is hopeless, because "the polyp's feeler" reaches everything and everybody. A police inspector and a deputy public prosecutor try to prove that the architect in the city is in the mafia.