The full title of the first edition read Ozma of Oz: A Record of Her Adventures with Dorothy Gale of Kansas, Billina the Yellow Hen, the Scarecrow, the Tin Woodman, the Cowardly Lion and the Hungry Tiger; Besides Other Good People Too Numerous to Mention Faithfully Recorded Herein. It bore the following dedication: "To all the boys and girls who read my stories – and especially to the Dorothys – this book is lovingly dedicated."

On an ocean voyage with her uncle Henry to Australia, Dorothy is blown into the sea by a storm. She takes refuge on a floating chicken-coop, which washes ashore, along with the coop and a hen in it. The hen is able to speak; Dorothy gives it the name "Billina". Exploring the land, Dorothy and Billina are menaced by a tribe of brightly dressed "Wheelers", who have wheels instead of hands and feet. They also find a clockwork man named Tik-Tok (one of the first intelligent humanoid automata in literature), who joins them.