A Walking Shadow introduces Detective Inspector Gilbert Markham and his teacher girlfriend Olivia Mullen. After two skeletons are discovered in the grounds of St Mary's Choir School, rising star DI Gilbert Markham, assisted by veteran old-timer DS George Noakes, investigates. When murder strikes again, Markham and Noakes embark on a quest to uncover a trail of savage killings and the horrifying truth behind them. Forced to think the unthinkable, they encounter hostility from within the force and their local community. As the web of corruption and deceit unravels, events hurtle to a shocking and explosive climax. Markham and Noakes finally solve the mystery, but not before Markham has been forced to confront long-buried secrets from his own past and seen his girlfriend exposed to deadly peril.