Anatol invites five of his oldest friends to his family home in the Wiltshire countryside to celebrate his 30th birthday. At his request, they play a game of his invention called Motive Method Death. The rules are simple: Everyone chooses two players at random, then writes a short story in which one kills the other. Points are awarded for making the murders feel real. Of course, it’s only natural for each friend to use what they know. But once they’ve put it in a story, each secret is out. It’s not long before the game reawakens old resentments and brings private matters into the light of day. With each fictional crime, someone new gets a very real motive. Can all six friends survive the weekend, or will truth turn out to be deadlier than fiction?

There are rules for murder mysteries. There must be a victim. A suspect. A detective. Grant McAllister, an author of crime fiction and professor of mathematics, once sat down and worked them all out, publishing seven perfect detective stories to demonstrate the rules of murder. But that was 30 years ago. Now Grant lives in seclusion on a remote Mediterranean island --- until Julia Hart, a sharp, ambitious editor, knocks on his door. His early work is being republished, and together the two of them must revisit those old stories. But as she reads the stories, Julia is unsettled to realize that there are parts that don't make sense. Intricate clues seem to reference a real murder --- one that's remained unsolved for 30 years. If Julia wants answers, she must triumph in a battle of wits with a dangerously clever adversary.