Ozma of Oz: A Radio Dramatization (Oz, Book 3‪)‬

Dorothy Gale, on a voyage at sea, is tossed overboard during a storm. She is washed ashore at Ev, a country neighboring Oz, where she meets up with her old friends the Scarecrow, the Tin Woodman, and the Cowardly Lion. She also meets Ozma, the new Princess of Oz, who has come to Ev on a mission of her own, which will bring them all in contact with the nefarious Nome King.