Geronimo Stilton's ancient ancestor Geronimo Stiltonoot is back in another prehistoric adventure. Geronimo Stiltonoot and his family are off to find a cure for Grandma Ratrock's aches and pains. She's heard that a remedy hides in a legendary valley, and Geronimo isn't even sure it exists. Little does he know that getting there will be an adventure among geysers, volcanoes, and rivers of molten lava.

Geronimo Stilton visits Australia where he has an adventurous time dodging sharks and snakes, and getting lost in the Outback.

After receiving a mysterious message summoning him to a meeting, Geronimo Stilton finds himself back in the Kingdom of Fantasy, summoned by the Elves, who want him to travel to the Great Explanatorium to find an answer to the earthquakes that are threatening the Kingdom.

When Space mouse Geronimo Stiltonix helps an alien spacecraft get back to its home planet, their queen becomes enchanted by Geronimo, and tries to force him to marry her and stay on the planet Flurkon forever.

Invited by the Queen of the Fairies to return to her kingdom and help in the quest for the true heart of happiness, Geronimo soon finds himself on an adventurous journey riding on the wings of a rainbow-colored dragon through seven fantastic lands.