During a New York City parade, an inflated balloon escapes and carries two African-American children, sister and brother Junipee and Stot (Juniperea and Aristotle) to Oz. There, they meet Ruggedo; he agrees to send them home, if they can help him regain his Magic Belt. In Ozma's royal palace in the Emerald City, a demonstration of the Wizard's newest device goes awry; it shrinks the assembled company, which includes many of the "celebrities," down to miniscule size. Through odd circumstances, the two Oz felines, Eureka and the Glass Cat, end up guiding two parties to the underground Land of the Mangaboos. Bungle, the Glass Cat, guides Ruggedo and the children, while the shrunken Ozites ride on Eureka's back. The parties meet for the climax of the plot.
Dickerson draws heavily upon the subterranean world depicted by Baum in Dorothy and the Wizard in Oz. Temporally, the author follows the tack of many modern Oz writers, and sets his tale in the present time, a century after the events in Baum's earliest Oz books — though it is not clear how Ruggedo got to be living in a cave in Oz at the story's start.
The author uses a wide range of verbal invention for his story, creating imaginative subplots and scenes. The miniscule Ozites meet a community of mice living within the royal palace. The Rodential Republic of Eroveechkeevna has not one but two presidents, Harcheevchack and Sorgheefdrock. Torseechundo is the ambassador from the Republic of Beevboobrala.
Visiting the lobster-like Sandamander people, Ruggedo's party meets their leader, The Admiral Whose Name Shall Not Be Pronounced, his wife, She Who Must Not Be Obeyed, and their aide, Minor Character of Little Importance.