Geronimo Stilton is the editor of the Rodent's Gazette, the most famous paper on mouse island. In his free time he loves to tell fun, happy stories. In this adventure, Geronimo has to face his worst enemies, the Pirate Cats, who have discovered a way to travel back in time and change history. Catardone III and Bonzo are in Amboise, France, in the year 1517 in the middle of the renaissance! They're out to steal Leonardo Da Vinci's most famous painting, the Mona Lisa! But this time, they have a new plan that may keep Geronimo Stilton and his friends from ever stopping them again!