Geronimo Stiltonix takes MouseStar 1's broken computer to a distant planet to be repaired by a brilliant inventor, but pirate spacecats attack and steal the device, and the spacemice must retrieve it before the machine can be turned against them.

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

Geronimo Stiltonix and his spacemice crewmates travel to a planet where delicious mozzarella grows in order to restore harmony between its alien inhabitants and the cheese-loving slurp monster.

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.

Discovering that the gift-distributing Elfix aliens have disappeared as the Night of Dancing Stars approaches, Geronimo Stiltonix and his spacemice crewmates race to find the missing aliens before the celebration is ruined.