Detective Inspector Helen Grace has spent her whole life running. From the past. From herself. From everyone who's ever tried to get close to her. She's spent her whole life hiding. Behind the badge. Behind her reputation as one of the country's best detectives. Until - framed for murder - she became one of its most high-profile prisoners. Now there is nowhere to run. Nowhere to hide. Because HMP Holloway is a place of dark days and long nights with dangers at every turn. Despised by the inmates and reviled by the guards, Helen must face her nightmare alone. And then a carefully mutilated body is found in a locked cell. Now Helen must find a ruthless serial killer. Before the killer finds her.