Berti and Boni of the forensic team investigate the murder of a Senegalese man outside the nightclub where the immigrant worked as a waiter. Fontana returns from his trip to Calabria and immediately confronts Neri, awaiting the trial that, according to his lawyer Mantovani, will clear him of all charges. Marcello promises the boss that his friend Nina will have justice and immediately returns to duty at the X Tuscolano, welcomed with joy by all the officers. Marchetti is forced to confront his painful past, as the investigation into the murder of the owner of an arcade leads Anna to suspect Massimo Sepe, son of the criminal killed by Raffaele years before and now an employee of the victim. In the meantime, Cristina, wife of Commissioner Fontana, discovers that Matteo, at school, has received an explicit threat to their safety from two strangers.