Sky Island is the sequel to Baum's The Sea Fairies. Trot is the young daughter of a California schooner captain. She is accompanied by Captain Bill -- an old sailor with a wooden leg who was her father's captain. Trot meets Button-Bright, a boy using a magic umbrella to travel from his home in Philadelphia. Trot, Button, and Captain Bill decide to travel with the umbrella, which takes them to a literal island in the sky. Sky Island is divided in half, one side pink, and the other blue, and the blues and pinks are at war. Trot, Button, and Captain Bill are imprisoned, and must somehow escape and end the conflict so they can return home.
"Hello," said the boy. "Hello," answered Trot, looking up surprised. "Where did you come from?" "Philadelphia," said he. "Dear me," said Trot, "you're a long way from home, then." "'Bout as far as I can get, in this country," the boy replied, gazing out over the water. "Isn't this the Pacific Ocean?" "Of course." "Why of course?" he asked. "Because it's the biggest lot of water in all the world." "How do you know?" "Cap'n Bill told me," she said. "Who's Cap'n Bill?" "An old sailorman who's a friend of mine. He lives at my house, too— the white house you see over there on the bluff." "Oh; is that your home?" "Yes," said Trot proudly. "Isn't it pretty?" "It's pretty small, seems to me," answered the boy. "But it's big enough for mother and me, an' for Cap'n Bill," said Trot. "Haven't you any father?" "Yes, "ndeed. Cap'n Griffith is my father, but he's gone most of the time, sailin" on his ship. You mus' be a stranger in these parts, little boy, not to know 'bout Cap'n Griffith," she added, looking at her new acquaintance intently.