Rinkitink of Oz is the 10th Oz book. In this story, you meet a kindhearted king named Rinkitink. When the king sails for a visit to the island kingdom of Pingaree, he and his talking goat, Bilbil, are welcomed with open arms. Before long, Rinkitink's lighthearted ways and merry songs endear him to the king and queen of Pingaree, as well as to their son, Prince Inga.
But when the peaceful isle is invaded, everyone from the rulers to the smallest child is taken off in chains. Only Prince Inga, Rinkitink, and Bilbil escape and so the three friends set out--aided by the magical Pearls of Pingaree--to rescue the prince's people. Their dangerous quest takes them across the vast Nonestic Ocean to the dreadful islands of Regos and Coregos to the dark underground domains of the Nome King. Just when they are needed the most, Dorothy and the Wizard of Oz arrive to lend a hand.