Dori and Em, Dorothy Gale's modern-day descendants from the previous book, return in this second installment. Dori travels to Oz in answer to a summons from Princess Ozma, while Em remains behind to deal with their parents' impending divorce. Ozma asks Dori to travel with Prince Inga to the Nome Kingdom; there they will aid Prince Rik to take control of the throne and avoid a war. The adventurers must defeat an Iron Giant and confront monsters on their way; they meet mermaids and invisible children.
