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...