Geronimo Stilton, famouse news reporter and editor-in-chief of The Rodent's Gazette, is on the adventure of a lifetime! First, he finds an old treasure map in an envelope for a mysterious stranger. Geronimo and friends are off to find the treasure, so they can return it. Then, Geronimo is busy, busy, busy. Geronimo visits a specialist, the Great Ratswami, but now that Geronimo can snooze, there's crime all over New Mouse City and he's still so tired! Finally, it's time to get physical when Geronimo is invited to a rat-jitsu martial arts championship. But once again mystery abounds-the winners of the match keep disappearing!