Inspector Trombetti returns fire during a police operation in a dark garage. When the lights come on, the body of a local gangster is found, but he was unarmed. Trombetti is suspended, and there are even rumours that he once worked for the gangster. Coliandro, convinced of his friend's innocence, clears Trombetti and discovers who the dishonest cop really is, all with the help of the gangster's sister, with whom he falls in love.