Geronimo hunts the thief who stole the precious Black Papyrus from New Mouse City's Egyptian Mouseum.

When Thea goes missing along with an ancient Mayan necklace, Geronimo Stilton is fast on the case, scouring Chichén Itzà for clues to find them.

"Yes, it's true--I'm a total 'fraidy mouse and the biggest worryrat. In fact I'm the complete opposite of my super-sporty and very brave friend Bruce Hyena. That's why I couldn't believe it when he dragged me off on a series of outrageous adventures to toughen me up. I had to keep reminding him that I'm not a supermouse! Or am I?"--P. [4] of cover.

When Wild Willie showed up at my door and invited me to travel with him to Japan, I jumped at the chance. We were in search of an ancient, legendary samurai scroll that holds the secret to a long-lost fighting technique. The scroll had fallen into the wrong hands, and it was up to me and Wild Willie to track it down and save the day. But first, we would have to fight a group of talented ninjas. Holey cheese -- this would be one adventure I would never...

The enchanted Winged Ring which Queen Blossom gave to Geronimo is missing, apparently stolen by the dark fairy Wither and her dark crow allies, and whoever possesses it gains enormous power and can travel between the Kingdom of Fantasy and the real world--now nightmares are starting to affect Mouse Island, the entire Kingdom is furious with Geronimo, and it is up to one mouse to set things straight and recover the ring.

Once again Geronimo is summoned to the Kingdom of Fantasy, and this time he must rescue five princesses of The Kingdom of Lotus Flowers who have been kidnapped by a terrible witch--but first he must journey to the Island of Dragons to find the bravest, the wisest, the silliest, and wittiest, and the most sincere dragons who prophecy says will aid him in his mission.

Drawn once again into the Kingdom of Fantasy, Geronimo discovers that the Land of Books is being threatened by a wave of grayness spreading from the Kingdom of Swamp Valley rotting books and turning all the characters gray, sad and worried--and it will be up to Geronimo, Winglet (daughter of Blossom and newly crowned empress), and the intrepid characters from fiction who join them along the way, to locate the source of this new evil and put a stop...

Geronimo, Thea, and their cousin Trap explore an old castle built by Grant Gentlemouse, the founder of New Mouse City, and when they find one hundred keys and only ninety-nine doors inside, they set off in search for the missing room.