Coliandro believes Gamberini has relapsed into his old gambling habit and, trying to help his friend, infiltrates an underground gambling ring. However, in doing so, he undermines an ongoing investigation initiated by Longhi and puts Giacomino, whom he has hired as a consultant, Gamberini, and himself in grave danger. Thanks to the help of Ambra, the girlfriend of one of the gangsters, the inspector manages to escape.