A dismembered corpse is discovered in the vault of a silver shop. The police initially believe it to be that of a convicted armed robber - but not everyone agrees with that theory. One of them is Decima Mullins, who calls on the help of private detective Cormoran Strike as she's certain the body in the silver vault was that of her boyfriend - the father of her newborn baby - who suddenly and mysteriously disappeared.

The more Strike and his business partner Robin Ellacott delve into the case, the more labyrinthine it gets. The silver shop is no ordinary one: it's located beside Freemasons' Hall and specialises in Masonic silverware. And in addition to the armed robber and Decima's boyfriend, it becomes clear that there are other missing men who could fit the profile of the body in the vault.

As the case becomes ever more complicated and dangerous, Strike faces another quandary. Robin seems increasingly committed to her boyfriend, policeman Ryan Murphy, but the impulse to declare his own feelings for her is becoming stronger than ever.