Assistant Chief Constable Desmond Iles's absence from a police undercover conference sets the stage for the moral and practical dilemmas faced by one of his colleagues, ACC Esther Davidson, as she works to bring down the largest gang operating in her sector. The role of undercover agents-or "out-located" officers-is brought into sharp focus as James masterfully unfolds the story of Davidson's decision to infiltrate the gang against the events of the resulting court case.