On the banks of the Baztán River in the lands of Navarra, the naked body of a teenage girl is found under circumstances that link this crime to a murder that occurred a month ago. Inspector Amaia Salazar leads the investigation, which takes her back to the town of Elizondo, where she grew up and has tried to escape from it her whole life. Faced with the complicated ramifications of the case and her own ghosts, Amaia's investigation is a race against time to catch a relentless killer in a land fertile with superstitions and witchcraft.