Every year for 10 years, a young woman's body was found in Edinburgh at Christmastime: naked, throat slit, body washed clean. The final victim, Kirsty Summers, was Detective Constable Tony McLean's fiancee. But the Christmas Killer made a mistake and McLean put an end to the brutal killing spree. Twelve years later, and a fellow prisoner has murdered the Christmas Killer. But with the festive season comes a body; naked, washed, her throat cut. Is this a copycat killer? Was the wrong man behind bars all this time? Or is there a more sinister explanation? McLean must revisit his most disturbing case and discover what he missed before the killer strikes again...