During a nocturnal chase in the streets of Bologna, a girl steals his gun from Coliandro. While trying to track down the unknown, the inspector comes across a dangerous criminal organization.

On the estate of a very wealthy man, an escort is cruelly murdered at the hands of a cold and determined assassin. The investigations lead Coliandro to confront the world of high class prostitution.

Coliandro must defend Remedios, a beautiful deaf girl, the only witness to the trafficking of a Latin American gang.

Coliandro believes that Gamberini has relapsed into the old habit of gambling and, trying to help his friend, infiltrates a clandestine gambling ring. In doing so, however, he blows up an investigation already underway promoted by Longhi and puts Giacomino, who he has hired as a consultant, Gamberini and himself in grave danger. Thanks to the help of Ambra, the girlfriend of one of the criminals, the inspector still manages to get away.