The fourth book in Baum's Oz series, Dorothy returns to lands of magic and fantasy with her cousin Zeb, kitten Eureka, and a cab-horse named Jim. They encounter vegetable people living under the world, and Dorothy is reunited with the Wizard of Oz when he floats down in his hot air balloon. They later are aided by invisible people in the Valley of Voe, and must escape several unfriendly mythical creatures to return to Oz. Baum's vivid imagination and creativity are readily apparent in this adventurous work, for he combines wonderful characters with an entertaining plot in a land at once familiar and full of enigmatic possibility.