Cat in the Stacks Mystery #9. Charlie is spending time helping a kind, elderly man navigate the library's genealogical database. But he's shocked when he learns that the visitor's search is focused on a member of his own family: his late aunt's husband. Charlie befriends the man and considers inviting him to stay in his home, but he's soon given reason to question that notion. True-crime writer Jack Pemberton is certain that Charlie's new house-guest was involved in a shocking homicide that took place years ago in a small town near Athena. As this cold case heats up, Charlie and Diesel have to uncover a killer who may already be too close to home. . .