What begins as a relaxing vacation turns into a time-traveling adventure, where Geronimo Stilton must travel to Khanbalik, or "The City of Khan" (modern day Beijing) in 13th Century China where he encounters Kublai Khan and Marco Polo. This time, Geronimo and friends must stop the Pirate Cats from corrupting Marco Polo's famous book "The Travels of Marco Polo," and changing history forever!

The Pirate Cats decide to better their offs by getting rid of Professor Volt ; kidnapping him and leaving him in the Cretaceous Period- a time when the earth was occupied by dinosaurs society. Geronimo and his friends must travel back in time 140 million years to save Professor Volt from literally becoming a part of history!

When Geronimo Stilton finds out that the Pirate Cats are going back in time to Venice in the year 1517, he knows they must be after one thing: The Mona Lisa! Geronimo and friends must travel to Renaissance Italy to stop the Pirate Cats from stealing the Mona Lisa and taking credit for what is arguably the world's most famous painting. But the Pirate Cats have an ace up their sleeve: someone in Geronimo's crew is an imposter!

Traveling to France during the reign of Louis XIII, Geronimo and his friends enlist in the "mouseketeers" only to discover that the mouse on the throne is an impostor and together they must find the real Louis.

"Japan, 1603, Geronimo and his friends don't know why the pirate cats went back to this precise point in time, but they are sure the pirate cats are up to no good! Posing as a traveling troupe of actors, Geronimo somehow manages to convince the locals that he's really a shogun, and not the first samurai! Will Geronimo be able to uncover the pirate cat's plan in time to stop them? Or have the pirate cats finally won?"--From the publisher.

Geronimo Stilton travels back in time to try and stop the Pirate Cats from infliltrating the Roman Senate and taking credit for building Rome's largest amphitheater, the Colosseum.