Geronimo Stilton Spacemice #7: Beware! Space Junk!

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?