Following Giulia Corsi's transfer, her deputy Roberto Ardenzi becomes the new commissioner of the X Tuscolano. During the inauguration ceremony, a gang of ferocious robbers breaks into the villa of a rich notary, easily deactivating the alarm system. One of the criminals shoots the professional's twenty-year-old son in cold blood, killing him. The cruel action sparks the rebellion of the only foreigner in the group, the Romanian Artur, who is killed after he announces his intention to leave the gang. Following an action conducted with the new commissioner Roberto, Mauro is taken hostage by the two brothers from Puglia led by the Neapolitan Gabriele, responsible for bloody robberies. Alessandro Berti of the Scientific Police offers himself as bait, allowing Roberto to hide and be taken to the hideout where his friend is about to be executed. After a terrible firefight, Mauro is freed by his colleagues.