In this gripping fourth season, Commissioner Giulia Corsi will have to deal with her father's murderers, who will do everything they can to stop the agents of the Tuscolano Tenth in their investigation, hitting the Commissioner where she is most dear.
Mauro, is engaged in a difficult anti-drug operation. In the meantime, the wedding between Commissioner Giulia Corsi and Inspector Paolo Libero is about to be celebrated. Ardenzi is taken hostage by a bandit during the anti-drug operation. Commissioner Corsi and Paolo Libero investigate a heroin trafficking inside a warehouse of slaughtered animals. In the meantime, Francesca gets back in touch with Ardenzi. Ingargiola buys a beautiful motorbike that, however, hides many dangers.
While Giulia is still trying to shed light on what happened ten years earlier - the day of the assassination of her father, Judge Corsi - a particularly delicate situation arises at the 10th Tuscolano police station: a man, who had just been evicted, reacted to the police by shooting from the apartment in which he had barricaded himself, then opened the gas cylinder and took a little girl hostage. Ardenzi and Belli are trying to track down a robber, while Ingargiola, Vittoria Guerra and Parmesan receive a series of strange reports from men who claim to have been robbed under a specific overpass, all in different circumstances. Meanwhile, Giulia receives important revelations about her father's murder.
This time Mauro and Roberto are engaged in a desperate chase: a woman has kidnapped her eight-year-old daughter from school and, in a state of delirium, has involved her in a crazy car race to reach her husband's lover, whom she holds responsible for the failure of her marriage. Meanwhile, Parmesan discovers that his credit card has been cloned and that a lot of money has disappeared from his account. After a tough confrontation with her sister Sabina, who until now was unaware of the reopening of the case concerning her father, Giulia decides to continue the investigation anyway, with the strong support of Paolo. Meanwhile, a pregnant woman who has just suffered a sexual assault arrives at the Decimo Tuscolano. All suspicions seem to fall on her ex-boyfriend, who, however, has an ironclad alibi.
Giulia asks her collaborators to solve the case concerning her father: Paolo and Luca identify a suspect. While Mauro and Roberto deal with their mutual problems regarding their private lives, a homeless man is found murdered in a park and the two agents immediately begin their search for the culprit. Unexpected news reaches the Decimo Tuscolano. In fact, while Roberto, happy about some sentimental news, receives the official transfer letter, Mauro discovers that a friend of his, an aspiring boxer, is in a coma in the hospital after being violently beaten. The agents understand that the victim is involved in a clandestine betting ring and Paolo, who has years of kickboxing training behind him, offers to go, as an infiltrator, to the gym frequented by the beaten boy.
While Giulia is in the hospital, the activities of the Decimo Tuscolano do not stop. Ingargiola, Vittoria and Parmesan investigate the case of a girl who ended up in a coma due to a drug used to lose weight; Luca and Roberto deal with a boy who passes himself off as a policeman by giving punishments to small-time criminals; Paolo and Mauro, instead, try to understand the causes of Giulia's accident. Giulia returns to the police station more combative than ever, determined to frame Greco, with the help of Mauro and Paolo. In the meantime, however, she must solve a new case: a young man is found dead in his pizzeria. The sister of the murdered man accuses her father, but the real culprit will soon come out into the open.
At the X Tuscolano comes the shocking news of a minor who is in a coma after accidentally ingesting cocaine. Mauro immediately goes to the hospital and discovers, with great astonishment, that the accused is Ardenzi and the victim is his daughter, little Mauretta. Meanwhile Ingargiola receives the complaint of a woman whose wallet has been stolen, and realizing that it is his first love as a child, he loses himself in nostalgic memories. The District agents work on the case of the discovery of a body on the banks of the Tiber and discover that the victim, a photographer responsible for an environmental association, was investigating the deliberate pollution of the river. In the meantime, five people who escaped the fire of a local supermarket arrive at the police station and are looking for the hero who saved them by opening an escape route for them. And who knows, maybe it's someone who works at the Decimo Tuscolano.
Mauro and Roberto investigate the death of a young man who was hit by a car going at high speed and discover that he was involved in a clandestine car race. Meanwhile, Mauro's father, Tiberio, has been the victim of a financial scam, losing twenty thousand euros, half of which belonged to his son. Giulia calls an expert, Prof. De Santis, in search of the truth about the new discoveries related to her father's case. That evening, at the town hall, Paolo is waiting for her to finally celebrate their wedding. A man in a deep depression kills his wife and her new partner. The daughter, who learns of the tragedy on the news, turns to the Decimo Tuscolano, who immediately offers her protection. Soon, however, the girl's father will try to track her down. Ugo and Ingargiola, meanwhile, investigate the disappearance of two elderly ladies. Paolo notices that Sabina, Giulia's sister, is in crisis over what has been discovered about her father and decides to get to the bottom of the research.
At X Tuscolano, the arrival of a new agent, Corrado, presumed son of Ingargiola, is celebrated. Luca immediately involves him in reporting a robbery at a gas station by two motorcyclists, unrecognizable because of their helmets. The young man's debut in the police force will not be very simple. Giulia, meanwhile, very worried about the disappearance of Paolo who did not return home during the night, alerts Roberto and Mauro to explore every single lead in the area. The clues that the agents find to trace Paolo are not, however, very comforting. While the desperate search for Paolo continues, a new case involves Luca and Corrado: the discovery of the body of a young Albanian woman, which will lead them to investigate a prostitution ring. Vittoria and Ingargiola, on the other hand, are busy solving a blackmail issue.
Giulia informs her sister of what happened to Paolo and, without giving herself peace, tries to find an explanation. Her colleagues advise her to take at least a day off. Meanwhile, Vittoria finds herself dealing with the case of Simone, a deaf-mute child who would like to attend a normal school. In addition, a sixteen-year-old is found dead in the courtyard of his school and Luca and Corrado begin to investigate. Thieves enter Mauro and Germana's house and steal the video camera with which Inspector Belli had filmed Giulia and Paolo's wedding day. Mauro cannot stand the idea of having lost that precious tape and launches into investigations. Luca and Corrado, on the other hand, try to solve a difficult case whose victim is a young woman, a chat lover, who is found suffocated in her home. Meanwhile, Vittoria and Ingargiola seem to be jealous of each other and Ardenzi receives a letter from Francesca.
After the robbery at Mauro and Germana's house, the couple moves to Roberto's house, significantly reducing his privacy with Francesca. But there's no time for personal complaints: the agents have to deal with a girl injured by an anonymous man who shot her from afar. It could be a sniper. Meanwhile, Ugo and Vittoria solve the case of a teacher who is the victim of obscene anonymous phone calls. Meanwhile, something happens between Ingargiola and Vittoria that they would never have expected. Mauro and Roberto run to stop a man who is blatantly about to shoot himself in the street. Giulia, in the meantime, continues to investigate Paolo's death, based on some photos examined by the forensic team.
While Mauro and Roberto investigate a twenty-year-old Algerian whose hand was amputated. Parmesan must deal with the complicated case of a mother and her daughter who were scammed by a supposed Filipino healer. Meanwhile, Luca and Corrado help Giulia in the investigation into Paolo's murder, following a man, Ira, who seems to have falsified his name. Mauro and Roberto don the unusual robes of friars in a cloistered convent to conduct investigations. In fact, a precious altarpiece, recently restored, has just returned to the convent, and the prior, suspicious of some tampering with documents, fears that someone wants to steal it. Giulia, meanwhile, collects the confession of a woman who was mistreated by her ex-husband, a particularly dangerous person, who is now about to be released from prison. The investigations into the mysterious Ira continue, bringing to light new disturbing truths.
While Mauro and Germana are in the hospital to collect the results of the tests performed to find out if they will be able to have children, a man takes a nurse hostage and locks himself in the room where his son, who is dying, is waiting for a heart transplant. Mauro will be able to intervene promptly and resolve the delicate situation. Meanwhile, the agents of the X° Tuscolano try to foil the attempted kidnapping of a child, based on some photos found in the basement where Ira worked. A series of latent tensions explode within the 10th Tuscolano. Vittoria is offended because Ingargiola is afraid to admit his feelings for her in front of his colleagues; Ugo wants to marry Adele but, at the same time, does not want to have to move to Argentina; while Luca is hurt by Corrado's attitude, who avoids him after discovering his homosexuality.
Roberto discovers that Francesca and Mauretta have been kidnapped, after which a phone call to his cell phone orders him not to ask anyone for help. Roberto soon discovers that there are clear and dangerous connections between the kidnapping and Paolo's murder, reaching the conclusion that the X° Tuscolano is being monitored through spy microphones. Meanwhile, Luca and Corrado deal with the case of a woman who disappeared after a car accident. Giulia and Mauro call the forensic team to remove the microphones hidden inside the police station. Someone who has free access to the rooms of the X° Tuscolano has managed to place them undisturbed, perhaps one of the most unsuspected people. The solution to all the mysteries is about to be revealed once and for all.
A man in a deep depression kills his wife and her new partner. The daughter, who learns of the tragedy on the news, turns to the Decimo Tuscolano, who immediately offers her protection. Soon, however, the girl's father will try to track her down. Ugo and Ingargiola, meanwhile, investigate the disappearance of two elderly ladies. Paolo notices that Sabina, Giulia's sister, is in crisis over what has been discovered about her father and decides to get to the bottom of the research. He discovers some details that will prove very risky for him.
At X Tuscolano, the arrival of a new agent, Corrado, presumed son of Ingargiola, is celebrated. Luca immediately involves him in reporting a robbery at a gas station by two motorcyclists, unrecognizable because of their helmets. The young man's debut in the police force will not be very simple. Giulia, meanwhile, very worried about the disappearance of Paolo who did not return home during the night, alerts Roberto and Mauro to explore every single lead in the area. The clues that the agents find to trace Paolo are not, however, very comforting.
While the desperate search for Paolo continues, a new case involves Luca and Corrado: the discovery of the body of a young Albanian woman, which will lead them to investigate a prostitution ring. Vittoria and Ingargiola, on the other hand, are busy solving a blackmail issue.
Giulia informs her sister of what happened to Paolo and, without giving herself peace, tries to find an explanation. Her colleagues advise her to take at least a day off. Meanwhile, Vittoria finds herself dealing with the case of Simone, a deaf-mute child who would like to attend a normal school. In addition, a sixteen-year-old is found dead in the courtyard of his school and Luca and Corrado begin to investigate.
Thieves enter Mauro and Germana's house and steal the video camera with which Inspector Belli had filmed Giulia and Paolo's wedding day. Mauro cannot stand the idea of having lost that precious tape and launches into investigations. Luca and Corrado, on the other hand, try to solve a difficult case whose victim is a young woman, a chat lover, who is found suffocated in her home. Meanwhile, Vittoria and Ingargiola seem to be jealous of each other and Ardenzi receives a letter from Francesca.
After the robbery at Mauro and Germana's house, the couple moves to Roberto's house, significantly reducing his privacy with Francesca. But there's no time for personal complaints: the agents have to deal with a girl injured by an anonymous man who shot her from afar. It could be a sniper. Meanwhile, Ugo and Vittoria solve the case of a teacher who is the victim of obscene anonymous phone calls. Meanwhile, something happens between Ingargiola and Vittoria that they would never have expected.
Mauro and Roberto run to stop a man who is blatantly about to shoot himself in the street. Giulia, in the meantime, continues to investigate Paolo's death, based on some photos examined by the forensic team.
While Mauro and Roberto investigate a twenty-year-old Algerian whose hand was amputated. Parmesan must deal with the complicated case of a mother and her daughter who were scammed by a supposed Filipino healer. Meanwhile, Luca and Corrado help Giulia in the investigation into Paolo's murder, following a man, Ira, who seems to have falsified his name.
Mauro and Roberto don the unusual robes of friars in a cloistered convent to conduct investigations. In fact, a precious altarpiece, recently restored, has just returned to the convent, and the prior, suspicious of some tampering with documents, fears that someone wants to steal it. Giulia, meanwhile, collects the confession of a woman who was mistreated by her ex-husband, a particularly dangerous person, who is now about to be released from prison. The investigations into the mysterious Ira continue, bringing to light new disturbing truths.
While Mauro and Germana are in the hospital to collect the results of the tests performed to find out if they will be able to have children, a man takes a nurse hostage and locks himself in the room where his son, who is dying, is waiting for a heart transplant. Mauro will be able to intervene promptly and resolve the delicate situation. Meanwhile, the agents of the X° Tuscolano try to foil the attempted kidnapping of a child, based on some photos found in the basement where Ira worked.
A series of latent tensions explode within the 10th Tuscolano. Vittoria is offended because Ingargiola is afraid to admit his feelings for her in front of his colleagues; Ugo wants to marry Adele but, at the same time, does not want to have to move to Argentina; while Luca is hurt by Corrado's attitude, who avoids him after discovering his homosexuality. Giulia, on the other hand, is disconcerted by Ira's ostentatious indifference towards Paolo's death, and does not know how to deal with him during the interrogation.
Roberto discovers that Francesca and Mauretta have been kidnapped, after which a phone call to his cell phone orders him not to ask anyone for help. Roberto soon discovers that there are clear and dangerous connections between the kidnapping and Paolo's murder, reaching the conclusion that the X° Tuscolano is being monitored through spy microphones. Meanwhile, Luca and Corrado deal with the case of a woman who disappeared after a car accident.
Giulia and Mauro call the forensic team to remove the microphones hidden inside the police station. Someone who has free access to the rooms of the X° Tuscolano has managed to place them undisturbed, perhaps one of the most unsuspected people. The solution to all the mysteries is about to be revealed once and for all.