Set shortly after the events in the first book, the protagonist is a boy named Tip, who for as long as he can remember has been under the guardianship of a witch named Mombi (who is the main antagonist) in Gillikin Country. As Mombi is returning home, Tip plans to frighten her with a scarecrow he has made. Since he has no straw available, Tip instead makes a man out of wood and gives him a pumpkin for a head, naming him Jack Pumpkinhead. Mombi is not fooled, and she takes this opportunity to demonstrate the Powder of Life that she bought from another sorcerer. She sprinkles the powder on Jack, bringing him to life and startling Tip, whom Mombi catches and threatens to turn into a marble statue. Tip leaves with Jack that night and steals the Powder of Life because Mombi plans to turn him into a marble statue in the morning. As they head for the Emerald City, Tip uses the Powder of Life to animate the Sawhorse so Jack can ride him (for even though Jack's wooden body does not tire, it can get worn away from all of the walking). Tip loses them as the tireless Sawhorse gallops faster and he meets with General Jinjur's all-girl Army of Revolt which is planning to overthrow the Scarecrow (who has ruled the Emerald City since the end of The Wonderful Wizard of Oz). Marching with the Army, Tip meets again with Jack, the Sawhorse, and now the Scarecrow as they flee the Emerald City in Jinjur's wake. The companions arrive at the castle of the Tin Woodman (who now rules the Winkie Kingdom following the Wicked Witch of the West's demise) and plan to retake the Emerald City. On their way back, they are diverted by the magic of Mombi (whom Jinjur recruited to help her apprehend them), joined by the Highly Magnified and Thoroughly Educated Woggle-bug, and aided by the Field Mice and their queen. Jinjur and her soldiers are scared by the Field Mice out of the main palace, but they still occupy the Emerald City itself. The Scarecrow proposes manufacturing a flying beast called a Gump by which they can escape through the air. Tip animates this collection of palace furniture with the Powder of Life, and they fly off, with no control over their direction, out of Oz and land in a nest of Jackdaws with all of the birds' stolen goods. In their attempt to drive the Jackdaws from their sanctuary, the Scarecrow's straw is taken away and the Gump's wings are broken. Using Wishing Pills they discover in the container holding the Powder of Life, Tip and his friends escape and journey to the palace of Glinda the Good Witch. They learn from Glinda that a girl named Ozma was hidden by the Wizard of Oz long ago and that she is the rightful ruler of the Emerald City, not the Scarecrow (who did not want the job anyway). Glinda discovered that the Wizard made three visits to Mombi, but not what they were for. She therefore accompanies Tip, Jack, the Sawhorse, the Scarecrow, the Tin Woodman, the Wogglebug, and the Gump back to the Emerald City to see Mombi. The witch tries to deceive them by disguising a chambermaid as herself (which fails), but manages to elude them as they search for her in the Emerald City. Just as their time runs out, the Tin Woodman plucks a rose to wear in his lapel, unaware that this is the transformed Mombi. Glinda discovers the deception right away and leads the pursuit of Mombi, who is finally caught as she tries to run across the Deadly Desert in the form of a fast and long-running Griffin (though later books state that anyone who touches the Desert is transformed into dust). Under pressure from Glinda, Mombi admits that the Wizard brought her the infant Ozma and that she used her magic to transform her into the boy Tip. At first, Tip is shocked to learn this, but Glinda and his friends help him to accept his destiny, and Mombi performs her last spell (although there is some evidence that she performed magic later on in The Tin Woodman of Oz)...