Margherita has been dead for three years now when Rocca meets Francesca, Tommy's teacher and daughter of one of his former superiors. The marshal investigates the death of the owner of a textile company in which children were exploited as workers; at first the father of one of these children accuses himself of the murder, but Rocca discovers that the real culprit is instead the son of the victim. The episode ends with the marriage between Daniela and Marco: a carabiniere and a policeman will live together!

The Marziales are an important family from Viterbo and in the garden of their villa a retired friend of Rocca's body is found, whose wife had died suspiciously, hit by a pirated car. Thanks also to the help of Francesca (who tutors a niece of the landlady), Rocca investigates the rich family, omertosa and hostile, reaching the solution of yellow.

A transvestite is the only witness to the murder of a man, found dead in a car outside a bowling alley. Even the waitress of the restaurant is later killed and suspicions seem to fall on her husband, but Marshal Rocca does not believe this is the case. In fact, the guardian of the restaurant is the real culprit, a murderer to avenge the death of his son.

A girl is found stabbed dead; she was staying in a Roman hotel. Rocca investigates her past and discovers that she had been kidnapped when she was ten years old: her parents, left broke following her payment, kill themselves. It is the kidnapper (owner of the hotel), whom the girl had recognized from a tattoo and who was following in her footsteps, who killed her. Francesca will figure out who it is from her tattoo and be saved by Rocca when the innkeeper tries to kill her.

A young pediatrician dies after drinking coffee in which a substance to which he was allergic was dissolved. Whoever killed him is not the father of a little dead patient, as it seems at first, but his nurse, in love with the doctor and unrequited. The woman had turned to a magician, later found lifeless in her home, to give her lover a love potion. Meanwhile, Francesca meets a man and informs Rocca that she intends to marry him.

Rocca is grappling with a series of crimes, which lead Mannino to think they are the work of a serial killer, who shoots a rifle belonging to a stolen batch of weapons. One of the victims is the perpetrator of the theft, Luca; the boy, together with a friend who worked at the gun shop, had planned to sell the rifles clandestinely. It is Rocca who discovers that the person responsible for the crimes is Luca's adoptive father, suffering from an incurable disease that made him lose his mind and led him to believe that his stepson had committed matricide. During the capture, the madman shoots the marshal who is saved thanks to his bulletproof vest.

Marshal Rocca tries to find the culprit of the murder of the parish priest of Santa Brigida, his friend, found killed in the same church. The killing of a journalist shortly afterwards allows the Marshal to discover that the culprit is the one who was posing as a simple witness to the murder of the parish priest.

A waitress, his former lover, is suspected of the murder of Michele Bono, found dead in a hotel. However, the subsequent death of a former police inspector leads Rocca to expose a gambling ring in the hotel. The assassin turns out to be the stepdaughter of Bono, her lover, whom she had killed with the motive of jealousy.

Marco is accused of ill-treatment and rape by an informant. Marshal Rocca is furious with his son-in-law for his daughter's betrayal, but he does not believe that Marco could have been capable of violence. He will later discover that the real culprits are the coach and attorney of a cyclist who fell into a coma due to the use of doping: the two had forced the girl to use Marco to sidetrack the investigation.

Father and son, managers of a fish market, are at odds with a mafia family because of the gambling debts incurred by their father. Thanks to the carabinieri, the two initially escape an ambush by criminals, but their son will later be found dead. Marshal Rocca will discover that the boy was actually the son of a wealthy entrepreneur and that the man's grandchildren are responsible for his death, eager to grab the entire inheritance.

Marshal Rocca investigates the murder of an art collector, killed in his home during a robbery. The stolen paintings, however, were fakes, and Rocca discovers that the perpetrator is the gang leader, in league with the murdered collector's wife. The perpetrator will also kill the other two thieves and one of their partners.

Rocca is faced with a case that seems to have to do with a satanic ritual. The discovery of a note inside a dead kitten with the inscription "Male returns healed" and, shortly after, the killing of a girl named Marisa, lead the Marshal to suspect a connection with the case of Professor Aleppi, of which he had occupied seven years earlier. In fact, the professor had been the director of an orphanage whose former pupils had founded a sect to avenge their deaths.

Marshal Rocca goes to Rome to attend the funeral of a cobbler friend and here he meets Benedetto with his wife Elisa, his old flame. Back in Viterbo, he begins to investigate the murder of a gas station attendant's son, which appears to be connected to two robberies. Meanwhile Rocca receives a visit from Elisa, who disappears after revealing that she is in crisis with her husband; Benedetto also arrives in Viterbo in search of his wife, whose car is found in a ditch. A woman friend of Elisa's is then found dead, who could be connected to the robbery and who also turns out to be the sister of a man arrested years earlier by Rocca because he was found guilty of killing a music teacher, loan shark and paedophile; he too is found dead in a farmhouse from the wounds sustained in one of the two robberies. Meanwhile Benedetto attempts suicide after the discovery of Elisa's body: the marshal will save him.

Benedetto confesses to Rocca that it was Elisa, the object of harassment, who killed the music teacher and that he had helped her to frame a man in her place. Once the sentence had been served, the latter had been hosted by the two spouses, oppressed by guilt; Elisa becomes his lover and accomplice in the robberies. Meanwhile, the marshal learns from his son Giacomo that the blood found near the cobbler's body belongs to Elisa's lover, who took refuge in his shop after a robbery: it is in this room that part of the booty will be found and it is by reconnecting the things that Rocca he will induce Benedetto to confess to the murder of his wife, her friend and the cobbler, all guilty of wanting to steal his share of his money. The assassin seems to want to follow Rocca to the barracks, but he commits suicide by jumping into the void. With Tommy and Francesca, the legendary marshal will continue his life in Viterbo.