He used to be celebrated for his finely tuned instincts and tenacity of character, but on his latest investigation, his personal demons are haunting him. DCI Walker recently drove his beloved Palestinian girlfriend, Salma, and her brother, Khalid, from the Gaza Strip through a border checkpoint. Khalid got out of the car and blew himself up, along with scores of innocent people. In the chaos, Salma and Joseph were separated. Now back in England, he's convinced she used him as a pawn.

Joseph starts work uncovering the links between the recent murders, in the concluding part of this urban thriller starring Marc Warren.