Years ago, bookseller and mystery aficionado Malcolm Kershaw compiled a list of the genre's most unsolvable murders, those that are almost impossible to crack, which he titled Eight Perfect Murders. But no one is more surprised than Mal, now the owner of a bookshop in Boston, when an FBI agent comes knocking on his door. She's looking for information about a series of unsolved murders that look eerily similar to the killings on Mal's old list. And the FBI agent isn't the only one interested in this bookseller. There is a killer out there, watching his every move, a diabolical threat who knows way too much about Mal's personal history, especially the secrets he's never told anyone, even his recently deceased wife. To protect himself, Mal begins looking into possible suspects and sees a killer in everyone around him. Suddenly, a series of shocking twists leave more victims dead, and the noose around Mal's neck grows so tight he might never escape.