Moldy Mozzarella! Geronimo Stilton is the Editor-In-Chief of the Rodent’s Gazette, the most fa-mouse newspaper on Mouse Island. In this series of time-traveling adventures, Geronimo’s archenemies, the Pirate Cats, have figured out a way to go back in time and change history for their own benefit. Geronimo and his friends must stop them before they change the world as we know it!
During Napoleon's 1798 campaign in Egypt, Lieutenant Pierre-François Bouchard found the Rosetta Stone. But he doesn't know that Pirate Cats have already replaced the original piece with their own version. Now it's up to Geronimo and friends find the real Stone and give it back to history!