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.