Geronimo Stilton travels back in time to save the future, by protecting the past from his arch nemeses, the Pirate Cats. These devious felines plan to change history to make them supreme rulers of Mouse Island! First, Geronimo and company join Christopher Columbus on his voyage from Italy to America in 1492 to stop the Pirate Cats from taking over the New World. Then, Geronimo Stilton and friends must travel back in time to Ancient Egypt! Next, the Pirate Cats travel to Rome, Italy in the year 80 CE to the opening of the Coliseum.