The 10th Tuscolano is dealing with a thorny affair involving a rising politician: his blue car has hit and killed an immigrant. Roberto does not give up and tenaciously sets out on the trail of the killer Ruggero, son of the building contractor Cesare Carrano. Mauro asks his friend Ardenzi for explanations about a secret that he has kept from him until now while, with Irene, he tries to prevent the fugitive from escaping. Ruggero Carrano is in prison and the prosecutor Forti authorizes the interrogation by the commissioner of the 10th Tuscolano. But the father of the murderer and his right-hand man are preparing a plan for a spectacular escape, while Mauro and Irene investigate the case of a sixteen-year-old who died of an overdose; the surprise is that the boy turns out to be the son of a friend of Mauro, whom he protected years before.