Cormoran Strike and Robin Ellacott are at odds following Robin's wedding to Matthew, but there's no time to mull on the new distance within their professional relationship, as a frightening visit from a potential client puts a new case on the table - and Robin and Strike set to work looking into reports of a strangled child.
With the detective agency thriving, the duo are also recruited to investigate the blackmail of a Government Minister and Robin is tasked with going undercover in the House of Commons.

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...

Robin discovers a startling truth close to home. The government minister's blackmailer becomes the prime suspect in the case, but Robin and Strike believe there was an accomplice.

Robin admits the truth to Strike, and a valuable clue helps them solve the case.