As DI Nicola Tanner investigates what appears to be a series of organised killings, her partner Susan is brutally murdered. Taken off the case, Tanner enlists the help of DI Tom Thorne to pursue a pair of ruthless killers. As the killers target their latest victim, Thorne takes the biggest risk of his career and is drawn into a horrifying and disturbing world. A Sunday Times Number One bestselling author.