DCI Jairus returns for his darkest outing yet as he finds himself pursuing a deranged serial killer with a taste for strangling his female victims and dressing in their clothes. But when Scotland Yard start digging into Jairus' last case and threaten to find him guilty of murder, the DCI needs help. He finds a friend and alibi in feisty forensic expert Cathy Durbridge, however it soon becomes clear that she's just as volatile and explosive as Jairus himself, and with his murderous past catching up with him, and Cathy becoming a liability, Jairus is desperate for a way out. So, when the devil calls and makes him an offer he can't refuse, he joins forces with a dangerous criminal gang, where to save himself he must commit the greatest sin of all. Can he survive with his soul intact?