In the depths of a freezing winter, Glasgow finds itself at the mercy of not one, but two serial killers. This is Detective Inspector Lorimer's worst nightmare and beyond anything he's faced in his years on the force. Can he find a link between the brutal slaying of prostitutes in the back streets of the city and the methodical killing of several unconnected businessmen?
Criminal investigating officer Hanne Wilhelmsen considers the possibility of a serial killer as she tracks down a series of numbers written in blood appearing on walls all over Oslo.