Rules for Perfect Murders

Specialising in mystery books, Old Devils is a Boston institution; a place where tourists come to snap photos with the shop's Instagrammable cat and browse first editions of Patricia Highsmith novels. Malcolm Kershaw, its owner, lives a quiet life, so he's surprised when an FBI Agent shows up one gloomy winter morning and asks him if he can answer some questions. Agent Gwen Mulvey is investigating a series of unsolved murders that appear to have one thing in common: each of the deaths bears an eerie similarity to the crimes depicted in several famous classic mystery novels. Malcolm doesn't know what to say - he doesn't know anything about the crimes, has barely even heard of the victims - but he certainly isn't expecting Agent Mulvey to bring up a blog post he wrote years ago. 'My Eight Favourite Murders', posted in 2004, was Malcolm's inaugural piece on the Old Devils site. Now, it seems, someone is using that list as a template; Agent Mulvey thinks Malcolm's specialist knowledge of the mysteries will help her solve the murders. But with each murder, the killer is inching ever closer to Malcolm himself, and the more Malcolm and Agent Mulvey learn, the less clear it becomes who is investigating whom.