Sampson Angus McKay is approached by his old friend, Chief Anthony Humbar, for help with an elusive serial killer who has been haunting him for 40 years: the Christmas Angel. The number of victims this heinous criminal has left behind has Sam and his team clawing at every possible lead, scrambling for answers and this time the stakes are even higher as the Angel has escalated his patterns. With the help of a disgraced psychologist and Humbar's old partner, the seven of them get closer than ever to apprehending their target, but things are not as they appear to be. Sam and his team's abilities will be tested as they go deep down the rabbit hole of justice to try and catch their most dangerous prey yet in this third Sam McKay thriller by K.M. Hardy.