When Geronimo's fears overtake him, Thea and Trap turn to survivalist Penelope Poisonfur, who leads the 'fraidy mouse into Rattytrap Jungle where he has to eat ant soup, swing on vines across raging rivers, and wrestle snakes.
When Geronimo Stilton's friend, Professor von Volt, discovers the location of the famous Ruby of Fire, Geronimo soon finds himself in a race to find the gem before it can fall into the hands of some dark characters.
Geronimo Stilton's relaxing vacation turns into a crazy treasure hunt in South Dakota, complete with a run-in with a mountain lion and a hot-air balloon ride to Mount Rushmore.
Geronimo joins the effort to rescue Blossom, Queen of the Fairies, who has been kidnapped by the Queen of the Witches and taken to the Kingdom of Nightmares.
Princess Sterling sends the Dragon of the Rainbow and Scribblehopper to bring Geronimo Stilton back the the Kingdom of Fantasy, because he is the hero in the dragon prophecy who will find the stolen dragon egg and restore harmony to the kingdom.