The inspectors of the 10th Tuscolano investigate the kidnapping of the fifteen-year-old daughter of a Romanian bookseller who hides a past as a policeman under the Ceausescu regime. Meanwhile, the investigations into Carlo's murder and the mysterious Russian woman he was in contact with lead Inspector Anna Gori and Commissioner Luca Benvenuto to the discovery of his possible involvement in drug trafficking. The investigations of the inspectors of the X° Tuscolano, assisted by the young inspector Gabriele Mancini, focus on the murder of a young aspiring cartoonist found dead in a ditch in the hamlet of Tor Pagnotta. The evidence seems to demonstrate the guilt of the caretaker of an exclusive residence in the area in whose swimming pool the young man used to clandestinely dive, but the investigations will reveal unsuspected background.