Magic Tree House
Junie B. Jones
Akiko's always prepared for something out of this world, but when she goes on a pleasure trip to Gollarondo with Poog, Mr. Beeba, Spuckler Boach, and Gax she can barely believe her eyes--Gollarondo is a city that was built completely upside down! Forget sight-seeing. All Akiko wants to do is keep both feet on the ground.
Which is not so easy. Almost as soon as the gang arrives Spuckler's robot Gax accidentally flies off one of Gollarondo's balconies and into the Moonguzzit Sea below. Good news: He survived the fall. Bad news: Anything and everything that falls from Gollarondo is automatically the property of Nugg von Hoffelhiff--the ruler of the seas beneath the city.
By the time Akiko and her crew are able to gain an audience with Nugg, he has sold Gax to others. What's worse, he actually broke Gax down into spare parts to maximize his profits! It's up to Akiko and the gang to retrieve the pieces of Gax before they are spread far and wide across the Moonguzzit Sea. But the people who bought the parts run the gamut from off the wall to downright villainous, so saving Gax's neck (and body and wheels) may turn out to be Akiko's most dangerous mission yet.
From the Hardcover edition.