Taking a well-earned break from the "Dearne Valley Demon" case, Detective Sergeant Hunter Kerr's rest is suddenly shattered when he witnesses a violent argument involving his father, shortly followed by a murderous road-rage attack upon his parents. As he delves deeper, Hunter uncovers disturbing facts and suspects that his father is harboring a sinister secret from his past: a secret which he is desperate to keep buried. In his father's native Scotland a sadistic and violent killer is on the rampage. Three retired detectives are found tortured and butchered. Is there a link? Or, is it someone who just likes killing cops? Hunter pushes and pushes to learn the truth, never realizing just how much danger he was placing himself, and those around him, in. In Barnwell, Hunter's working partner, DC Grace Marshall, recovering from her own psychological problems arising out of the "Demon" serial-killer investigation, is acting sergeant in his absence and soon finds herself in charge of her first major incident: a young woman's battered body is dragged from the freezing waters of the local country park.