When the corpse of young Ettore Frediani is found along a bank of the Tiber River, everyone figures it was a suicide. His father, Valerio, ex-cop with a past full of mistakes, both as a man and as a parent, is shattered with grief. And so too is his ex-wife Francesca, who even accuses him for what has happened to their son.

Valerio does some snooping to figure out who was on duty the night of Ettore's death, but he winds up on the receiving end of Chief Commissioner Tom's seething contempt. New at his post, the latter considers Valerio the lowest of the low, worse than scum: a bent cop. Thanks only to Luigi, one of the few ex-colleagues who still holds him in high esteem,

While Ettore's PC is analyzed by Forensics, Sara identifies the missing beggars. Valerio tracks them down at a substance abuse recovery center where the girl tells him that Ettore hadn't jumped into the river, but had been thrown into the water by two men; and it happened on Saturday and not Friday.

The shoe that Valerio had found along the banks of the Tiber oddly shows traces of another setting. As his ex-colleague working for forensics - Alessandro - explains, it definitely looks like Ettore had been in one of the travertine quarries outside Tivoli. Valerio asks Arturo, a retired agent from the K-9 unit to go with him together with his bloodhound Gandalf.

Sneaking into the offices of the PGS company, the private surveillance firm owning the vehicle that had dumped Ettore's lifeless body along the banks of the Tiber River, Valerio identifies those who could very well have been the material executors of the murder. Meanwhile the police arrest two prime suspects.

Valerio and Sara discover what had happened on the day of Ettore's accident: the boy had been on his way to a hotel in Rieti to help the Senegalese migrant Moussa and his family, who had been assigned a council house apartment on the outskirts of Rome, in the seaside area of Ostia, but who had then been bullied off the premises by a gang of local underworld toughs.

Valerio studies the movements of Ostia's leading pusher and on a calculated impulse, decides to rob him as a way of forcing to meet with his bosses. The gambit works and thanks to a GPS tracking device that Sara manages to get for him, he follows the trail all the way to the EUR neighborhood, where the man meets with two shady looking characters aboard a dark sedan.

Valerio discovers that his brother Gianni knows a lot more than what he wishes to let on and in all likelihood is involved in the death of his nephew. Tailing him, he discovers the existence of a real estate company that's connected to a host of foreign companies: one of these is called "Difrinae Ltd" (anagram of "Frediani"), with headquarters in London.