The body of a boy, Gilberto Ballarin, is recovered by police divers from the waters of the Venetian Lagoon. Elena Zonin, deputy commissioner of the CNCPO (National Centre for Countering Child Abuse Online) believes that Gilberto has been kidnapped by a network of pedophiles that she has been trying for years to identify and defeat. She arrives in Venice to deal with this case together with Deputy Commissioner Daniele Vianello, the great love of her youth.

The little Angelo escapes from the family home and goes to Venice convinced that he can meet Elisa, a girl he is chatting with. Elena and Daniele, thanks to the information they get from Karim, who lives on petty thefts and knew Gilberto well, catch a shady man called Cioro who admits to having met Gilberto on the day of his disappearance, but he denies that he had killed him. Elena, against the opinion of her colleagues, is convinced that Cioro is not Gilberto's killer.

Angelo wakes up in a dark room. Elena gets permission to resume the investigation together with a task force created to help her solve the case and dismantle the pedophile network. They discover that Gilberto, who believed he was chatting with a girl named Sofia and convinced that he was going on a date with her, was kidnapped.

The man who rented the boat with which Gilbert was kidnapped is called Pietro Tomà and he grew up in an orphanage. With the help of Daniele, Elena sneaks into his house and, investigating her computer, she discovers that the man was involved in the kidnapping of Gilberto and other children...

Elena goes to the family home where Angelo lived before his kidnapping and the psychologist who took care of him describes him as a strong boy despite his appearance. Elena, invited by Giulia, her childhood friend and now Daniele's wife, takes part in the birthday party of their eldest son, Emilio. Without getting noticed, however, she leaves the party and goes to Rome. There she meets her son Diego, who is going through the first teenage love crisis...

Elena and Angelo’s parents finally manage to enter the chat and, hiding behind a fake profile, to get a video of the imprisoned boy. They find out where he is, but the jailer manages to escape with Angelo before they arrive...

While Elena, who miraculously survived the accident, is in the hospital, Daniele and his men discover where Andrea, Angelo's jailer, has taken refuge. Andrea manages to escape again, seriously injuring one of the men of the task force, and he seeks refuge from what he believes, all his life, to be his Master. Meanwhile, someone has stolen all the documents he found in the orphanage from Elena's car.

Elena and Daniele, thanks to the testimonies of those who have been there, reconstruct the dramatic story of the abuses that were perpetrated in the orphanage. The suspicion that yesterday's pedophiles are the same ones who still act today through the infamous network becomes certain. But absolutely unexpected events call into question the last chapter of the investigation.