Geronimo Stiltonix is Geronimo Stilton of a parallel universe and he the captain of the spaceship, MouseStar 1. In this book, Geronimo sets on a fascinating adventure in the space. He flies to the distant planets and meets the inhabitants of the planets. He has an encounter with strange aliens whose spaceship and they desperately seek his help to fix their ship. Geronimo happily helps them and accompanies them to their planet Flurkon. The queen of the aliens gets mesmerized by Geronimo and wants to marry him. Will Geronimo be forced to stay on Flurkon forever, or will he manage to escape somehow?