The story begins where the previous book ended. Button-Bright is moping around the Royal Palace of Oz in the Emerald City, missing his absent friend Ojo. After witnessing Trot watch her mother in the Magic Picture, he decides to pay a return visit to his family in Philadelphia. Ozma sends him there with her Magic Belt. His uncle Bob reveals that Button-Bright was a foundling, and not his late parents' biological son. The boy borrows the family umbrella once again, and sets off on a journey to discover his true origins.