Rinkitink in Oz was published in 1916, and it has an unusual publishing history. Baum had written most of the novel as a non-Oz fantasy called King Rinkitink years earlier and reworked it to fit the Oz franchise. Much of the book accordingly takes place not in Oz at all but on the coastal islands of Pingaree and Regos and Coregos, far across the Nonestic Ocean.
The plot follows Prince Inga of Pingaree, whose family has been kidnapped after the conquest of his island home by the warriors of Regos and Coregos. With three magical pearls, the comically jolly King Rinkitink of Gilgad, and Bilbil the talking goat, Inga sets out to rescue his parents and reclaim his kingdom. The eventual journey takes them into the Nome King’s underground realm and finally into Oz proper, where Dorothy and Ozma resolve the situation. The book is sometimes criticized for its weak Oz connection but loved for Rinkitink himself, who is one of Baum’s most consistently entertaining minor royal characters.