Checkmate, cheese-lovers, er, we mean chess-lovers. For once, all is quiet in New Mouse City, so Geronimo Stilton, Editor-in-Chief of The Rodents Gazette can report on an incredible chess match-up. On one side, Gary Goudov, world-renowned chess champion, and on the other side, a super chess-playing computer! But after Geronimo leaves, the infamouse Gem Gang commits a string of robberies that only the Stiltons can untangle. Can Geronimo, Benjamin, and Thea protect the good mice of New Mouse City from the greed of the Gem Gang?