Professor McQueen is missing his cat, so decides to leave the Duodecimo Club (in London's Bibliography Quarter) and return to his lodgings at Timor Mortis College, Noxford. But on the train he meets his nemesis, the worst man in the world, the organizer of half that is evil and nearly all that is undetected in the city of books, the Napoleon of Bibliographical Crime. There is, however, still no sign of Cherrytop the Sarcastic Horse!