There is a crisis in the Starlight Kingdom, one of the fantasy worlds: its stars, powered by a special kind of stardust, are fading and may soon go out forever, leaving the Kingdom in darkness--so the Thea sisters and Will Mystery set out for Brightstar Castle to discover what is wrong, but first they must overcome the obstacles and challenges that the fairies are placing in their way.

When they receive a damaged message in a bottle from the Oofa Oofa rodents in the ancient far north, Geronimo Stiltonord and the micekings set sail to Oofadale but are attacked by a band of dragons while on their voyage.

Traveling to the planet Jurassix to warn its inhabitants of an imminent comet strike, Geronimo Stiltonix and his crew encounter ferocious, dinosaur-like beasts who have an appetite for rodents.

With a garbage thief on the loose in New Mouse City who is stealing organic waste, Hercule and Geronimo enlist the head of the Recycling Center to help, then discover that the thief has good intentions.

Geronimo Stilton's ancestor, Geronimo Stiltonoot, investigates a witness's claim of a moving mountain of ice.

Grandfather Shortpaws sends Geronimo Stilton on a hunt for his old friend, the Red Bandit, in Arizona.

MouseStar 1 is surrounded by floating space junk! It's yucky--and dangerous. It's coming from a nearby planet, Cleanix. Geronimo Stiltonix goes to visit, and discovers that the aliens there are very wasteful. Even worse, robots that they've thrown in the trash have started to rebel! Can the spacemice restore harmony before the robots take over?

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.

Geronimo and his friends participate in a treasure hunt set up by his rival and are determined to overcome all of its challenging obstacles, including tricky riddles and smelly dinosaurs.