When the bare physique of a teenage woman is discovered on the banks of the River Baztán, it’s rapidly linked to an identical homicide one month earlier than. Quickly, rumours are flying within the close by village of Elizondo. Is that this the work of a ritualistic killer or is it the basajaun, the ‘invisible guardian’ of Basque mythology? Inspector Amaia Salazar leads the investigation, taking her again to the center of the Basque nation the place she was born, and the place she hoped by no means to return. Shrouded in mist and surrounded by impenetrable forests, it’s a place of unresolved conflicts and a horrible secret from Amaia’s childhood that can come again to hang-out her. Confronted with the superstitions of the village, Amaia should combat the demons of her previous to confront the fact of a serial killer on the free. However as she is drawn deeper into the investigation, she feels the presence of one thing darker lurking within the shadows…