Geronimo and his friends travel to his cousin Stevie Stingsnout's wedding far away on Cheap Change Hill and run into trouble.

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.

Sometimes a busy businessmouse like me needs a nice, relaxing vacation. But of all the rotten rats' luck -- every time I tried to get away, disaster struck. My aunt Dizzy Fur's mouse hole caught on fire, my office was flooded, and our printing press broke down! When I was finally ready to depart, all the good trips were booked up. I was stuck in a flea-ridden old hotel, sharing a room with a bunch of Gerbil Scouts! I couldn't wait to get back to my...

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.