"A little man jumped out of the basket, took off his tall hat, and bowed very gracefully to the crowd of Mangaboos around him. He was quite an old little man and his head was long and entirely bald. 'Why,' cried Dorothy, in amazement, 'it's Oz!' The little man looked toward her and seemed as much surprised as she was. But he smiled and bowed as he answered: 'Yes, my dear; I am Oz, the Great and Terrible. Eh? And you are little Dorothy, from Kansas. I remember you very well.'"
An earthquake splits the earth under Dorothy, and she, her kitten Heureka, her cousin Zeb, and a horse named Jim fall into a city of glass. They are joined by the Wizard of Oz and nine piglets, and must wander through dangerous lands trying to find their way home.
First the meet the Mangaboos, who try to kill them by closing them in a black cave, but the friends escape by traveling through the cave and into the Valley of Voe. After escaping the invisible bears by rubbing their feet with a plant which allows them to walk on the water, they meet a man from the surface of the earth. He made holes, and one day he made a hole so large that when he looked down into it he fell onto this spot beneath the Earth's surface.
When they leave this man, who is making rustles for women's dresses to keep himself amused, they reach the wooden land of the gargoyles. They have a fight with the gargoyles made of wood. Even their wings are wooden, and hinged to their backs. However, they can't stand to hear noise. They talk to each other without speech and hearing noise makes them collapse. However, they are captured in the end and make their escape by stealing the wings of the gargoyles and strapping them to Jim the horse, who flies away with all of them in the wagon.
Continuing on their journey, the group had to travel through a cavern filled with Draonettes. They are baby dragons and their mother has tied their tails to the back of the cave so that they cannot eat Dorothy and her friends. But they say, "We will eat you in a wink if you come to close". The band of anxious travelers feel they must get through the cave quickly in order to avoid the Dragon mother, but when the reach the back of the cave, their is no exit. Of course, Dorothy just waits for Ozma to look into her magic picture to see that Dorothy is in trouble, and whoosh, the friends are all standing at the gates of Oz.
Then we are told the history of Oz and meet all the old friends who live there. Jim meets the Saw Horse, Cowardly Lion, and the Tiger with a conscience. Soon they have a parade and a picnic to celebrate the arrival of Oz and Dorothy. At the picnic, Zeb wrestles with a Munchkin and Jim races the Saw Horse.
When they get back to the palace, it seems that one of the little piglets is lost. Heureka is put on trial for eating the little white pig. If she is found guilty, Heureka will be put to death nine times. However, the piglet is found in a vase where he was hidding from the hungry kitten.
The kitten is shunned for her attempt at murder and begs Dorothy to let her leave Oz. Dorothy looks in the magic picture and sees her aunt and uncle in mourning over her death, and so they all go home.
This book is cute and funny, but not hilarious. Not a lot happens, and most of it is description or recaps of previous Oz books.