The movie begins in a forest near the small town of Bastan in Spain, where a young girl's body is found by a river. Inspector Amaya and the police arrive to investigate, discovering that the girl, named Inoa, was only 13 years old and had been strangled with a rope. Similarities to a previous case involving another girl, Carla, lead to suspicions of a serial killer. Amaya, a former FBI agent, takes charge of the case and stays in her hometown. Family dynamics and past abuse come to light as the investigation unfolds.