Louise Boni, maverick chief inspector with the Black Forest crime squad, is struggling with her demons. Divorced at forty-two, she is haunted by the shadows of the past. Dreading yet another a dreary winter weekend alone, she receives a call from the departmental chief which signals the strangest assignment of her career - to trail a Japanese monk wandering through the snowy wasteland to the east of Freiburg, dressed only in sandals and a cowl.

She sets off reluctantly, and by the time she catches up with him, she discovers that he is injured, and fearfully fleeing some unknown evil. When her own team comes under fire, the investigation takes on a terrifying dimension, uncovering a hideous ring of child traffickers. The repercussions of their crimes will change the course of her own life.