Marcello has screwed up and is now the object of an internal investigation. Luckily, Achille will train him for the interview, and a mysterious helper could save the day. Dario finds himself with a partner who is the last person he would want to work with: the boss' nephew. At dispatch, Perri tells Katia how she ended up under observation. And it would have been better if she hadn't said anything.

Marcello thinks he has found a way to save his marriage. Perri tries freeing herself from a difficult relationship that will end up engulfing the police station. Meanwhile, a phone call for the gangsters risks precipitating the events.