Return to Oz is a fantasy which carries on the story and adventures of Dorothy Gale. In the beginning of the story, Dorothy's aunt and uncle are concerned about her mental state of health because of her obsession with the events she remembers from her first visit to Oz. In an attempt to help her, they take her to mental hospital where the technique for dealing with people who suffer from depression or hallucinations is shock therapy. Dorothy manages to find her way out of the hospital and back in the magical land of Oz.
There are many differences in Dorothy's second visit to Oz. One difference is that her traveling companion is a chicken named Billina, rather than her dog Toto. Once they reach the land of Oz, Billina acquires the ability to speak. The yellow brick road leading to the Emerald city is broken and overgrown with weeds. Dorothy sets out to follow the road to the city in hopes of finding her former friends. Emerald city is also in shambles and overrun by beings referred to as Wheelers. These characters have elongated arms and legs with wheels for hands and feet, so they can travel quite quickly.
During the course of the story, Dorothy meets several new friends who help in her quest to conquer the bad witch. Tik-Tok is a mechanical man who needs to be wound periodically in order to keep running. Jack Pumpkinhead is another character who helps Dorothy with her quest. This character has the body of a scarecrow and the head of a Jack-o-Lantern. In addition to destroying the bad witch, Dorothy also learns her friend the scarecrow has been kidnapped by the Nome King.
When Dorothy meets with the Nome King he offers to release the scarecrow if she can find her new friends in a room filled with small objects. The friends have been turned into small objects themselves. One of the more fantastical additions to the story is the witch, who has the ability to change her head. She can replace her old, withered head with any of the beautiful, young heads she keeps on a revolving shelf.