Strike and Robin's startling discovery seems to confirm the story of the strangled child - but they're forced to leave the scene before they can properly investigate.Fearing their witness is in danger, they redouble their efforts to find him. As Robin deals with frustrations in her marriage and Strike accepts a dependency on a new girlfriend, their investigation deepens.The duo are taken all over London in pursuit of the truth, from a derelict warehouse filled with protestors to a high-society charity fundraiser. But ultimately, our favourite detectives are unable to stop another tragedy...