Coliandro must protect Giacomino, a peculiar, funny, and brilliant character who saw something he shouldn't have seen and is under death threat.

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.

Coliandro seems on the verge of a successful conclusion to his romantic adventure. But, just as things are going, Giacomino shows up at his house, sleepy, hungry, and handcuffed. The motive is incredible: Giacomino is accused of committing a series of brutal murders. To help his friend, Coliandro must hunt down the real serial killer.