This is the 4th book in the Oz universe and it came out in 1908. By the way, there are only 2 books in the Oz series that were illustrated with fancy watercolor paintings, and this is one of them. Just like in several other books in the franchise, some of the events in Dorothy and the Wizard in Oz take place outside of Oz.
The tale beings with Dorothy being excited and happy to join Henry, her valiant uncle, and visit some relatives that she hasn't seen for ages. They are successfully back from their hazardous vacation to Australia and are safe and sound. Soon, she meets Zeb, and together they hop onto a buggy when a horrifying earthquake strikes. The earth under them quite literally opens up and the kids fall deep into the planet's core. The team ends up in the Land of the Mangaboos, a weird species of vegetable folks.
These peculiar creatures claim that Dorothy and her friends were responsible for that violent quake and it's destroyed most of their fragile glass structures. Next, they sentence the poor kids to death, but, thankfully, a huge air balloon appears out of nowhere. The Wizard of Oz winks at Dorothy, letting her know that everything's gonna be alright. He fascinates the Mangaboos with his magic tricks and forces the prince to hire his as the royal wizard.
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)
However, the death sentence is not lifted and the "intruders" will be executed when a Mangaboo wizard becomes old enough to be the new magician. Eventually, the vegetable people force the travelers to leave their world and they end up in a whole another kingdom. Dorothy and the Wizard in Oz is a wonderful children's book that comes with the perfect formula: it's adventurous, funny, educational, talks about the importance of friendship and the power of love.