Geronimo Stilton : the invisible planet / Geronimo Stilton ; illustrations by Giuseppe Facciotto (pencils), Carolina Livio (inks), and Serena Gianoli and Paolo Vicenzi (color) ; translated by Julia Heim.
Discovering a planet that bafflingly appears and disappears, Spacemouse Geronimo Siltonix lands his MouseStar 1 ship to investigate and encounters a race of mysterious, secret-keeping aliens.