This is the 11th novel in the world-famous Oz series, and it came out in 1917. The story begins with the vanishing of Ozma, the princess of the Land, and it's up to Dorothy and the legendary Wizard to find her and to rescue her. Baum wrote in the introduction to this book that the idea of the Oz characters doing everything in their power to help Ozma out came from a little's girl's letter to the writer.
Dorothy wakes up one day and can't find the princess anywhere. She's not in her chambers or anywhere else in the palace. Glinda is having a hard day as well: her book of records is nowhere to be found, so, she tries to "cook up" a spell to locate it. Yet, her tools - all of her magical arsenal - are gone as well! She quickly dispatches a messenger to the city to let everyone know of the theft.
When the Wizard learns of Glinda's trouble, he offers to lend a helping hand and wants to give her his own tools, but they are missing as well. That's when the trio understands that something big is going on and that they're the only ones that can bring Ozma back and recover the lost magical tools. They start huge search parties for the princess, but there's still no sign of the royal lady or the tools.
Land of Oz works:
1. The Wonderful Wizard of Oz (1900)
2. The Marvelous Land of Oz (1904)
3. Ozma of Oz (1907)
4. Dorothy and the Wizard in Oz (1908)
5. The Road to Oz (1909)
6. The Emerald City of Oz (1910)
7. The Patchwork Girl of Oz (1913)
8. Tik-Tok of Oz (1914)
9. The Scarecrow of Oz (1915)
10. Rinkitink in Oz (1916)
11. The Lost Princess of Oz (1917)
12. The Tin Woodman of Oz (1918)
13. The Magic of Oz (1919, posthumously published)
14. Glinda of Oz (1920, posthumously published)
Then, the trio, accompanied by their good-old friends, including the boy who gets lost (Button-Bright), Trot, and others, leave the Emerald City and go out there into the big, scary world outside. They arrive at the previously uncharted lands of Thi and Herku. The inhabitants of these communities are keeping giants around and are using them as slaves. They've got a unique compound that gives them enough power to control the giant beasts. Soon, Dorothy and her friends encounter Ugu - the big villain...