It is 1969, and approximately six months since the shootings in the cathedral. Gently is taken by surprise when he learns of Bacchus's resignation, realising that his sergeant has lost his confidence. Still suffering his own scars from the incident, Gently sets about fixing Bacchus and insists that he help him investigate a death in custody - a case that has both Gently and Bacchus questioning what it means to be a police officer at a time when attitudes to the police are changing. Meanwhile, the victim's family ask the pertinent question: 'aren't the police supposed to protect us?'.

Gently and Bacchus delve into a world of army secrets when a young former soldier, Scott Tanner, commits a murder in a Turkish bath. Whilst investigating Tanner's history, Gently hears of horrific allegations of what some soldiers have to face from their own side. He is forced to question the uncomfortable truth of what it means to serve one's queen and country, as an event from the past presses on his conscience.