"Little Wizard Stories of Oz" is collection, published in 1914, of six short stories for particularly young readers that were published separately in 1913, when a desperate Baum realized he needed Oz to pay the bills. Most Ozophiles place it on the shelf just before "Patchwork Girl," as the six short stories form a nice little intro to the second era of Oz.
The story this comic is based upon ("Dorothy and Toto") features Dorothy learning a very valuable lesson: sometimes the Wizard is a dick. As Dorothy is out and about on a nature hike, she's kidnapped by a horrible magician who can shrink or turn into a giant at will. Upon being threatened with getting turned into a doorknob (because I guess that's a thing that happens), Dorothy is forced to clean the monster's house. After Dorothy has subsequently washed several hundred dishes, she discovers that the monster is - in fact - the Wizard, who was attempting to teach her a lesson about why little girls shouldn't be wandering around magical fairy lands alone.
As I said, sometimes the Wizard is a dick.
(Also, cue the "AND THIS IS WHY WE DON'T TEACH LESSONS!" quote from Arrested Development.)