Sky Island
 Being the further exciting adventures of Trot and Cap'n Bill after their visit to the sea fairies

by L. Frank (Lyman Frank) Baum

"Sky Island" by L. Frank Baum is a children's fantasy novel published in 1912. When Trot and Cap'n Bill join Button-Bright on a magical umbrella journey, they land on a floating island divided between two countries: the tyrannical blue side ruled by the cruel Boolooroo, and the cheerful pink side governed by modest laws. Trapped without their umbrella and facing threats from both sides, the travelers must navigate strange customs, escape imprisonment, and mount a daring rescue to return home.