The owner of a car dealership for the rich and famous is murdered, and at his funeral Carlo meets escort Anna Galinda. This is the last time anybody sees her alive. The police waste no time in making a connection between the two crimes and calling Monterossi in for questioning. But who was Anna in reality? And did she really know something about a hidden treasure?

The mysterious killer has been found dead, but the police are not the only ones looking for Sergio De Magistris. To find out the truth, Carlo has no choice but to talk to De Magistris' ex girlfriend Marzia, a girl who is scared and risking big.

The investigation by Police points toward Enrico Domini, a man who, years before, had been the prime suspect of a kidnapping case. Meanwhile, Carlo and his friends, in cahoots with Sargeant Ghezzi, find Anna's real home, along with other important clues.

Another death, another stone. Ghezzi and Carella are ousted from the investigations and must find a way not to throw in the towel. Meanwhile, two killers accept a job from an unlikely client and Monterossi makes a strange discovery. At odds with his parents, Nadir must ask his friend Francesco for hospitality.

There are three dead. Monterossi's discovery is a thin thread that takes you back in time, to a remote and dark past, into which Ghezzi and Carella begin to dig. Having landed in Reggio Calabria, the two killers try to orient themselves while Nadir plays at being a gangster and ends up in handcuffs.

Is Nadir the stone killer? Ghezzi and Carella find the right trail, a trail that, without knowing it, the two killers are also following. Meanwhile, Monterossi approaches the widow of the third dead man, a refined and cultured woman who fascinates and disturbs him.