Cristina Bini, a young babysitter, is stabbed to death by her ex Carlo Serra, a drug addict who stole her three-year-old daughter, Laura, who was with her. The little girl is the daughter of Lieutenant Nicola Riva, a colleague of Captain Davide Rea who is taking part in the search. Serra is found in the farmhouse where Paolo Libero was killed for the investigation into pedophilia and confesses to having given Laura to a stranger. Giulia confronts Pietro De Santis, the former criminologist in prison for child trafficking: the monster, in exchange for lifelong isolation, names Alfredo Castiglia, in whose house Laura is found, safe and sound. Giulia faces her past and Paolo's death, Rea is close to her.