Dorothy Anne Peridot and her uncle, computer programmer Joe Robertson, are sent to Oz by a mysterious virtual-reality game. They meet a game sprite, a nymph called ZIP, and set off down the Yellow Brick Road to find the Emerald City. Dorothy Anne and Uncle Joe (he is the grown-up of the title) hope that Princess Ozma will use her Magic Belt to send them home again. But they inadvertently bring about the reconstitution (from wood ashes in a stove) of the Wicked Witch of the East.
Just as the hundredth anniversary of Dorothy Gale's first arrival in Oz is about to be celebrated, Ruggedo the Nome King — last seen when he was magically transformed into a cactus at the end of Handy Mandy in Oz — is accidentally brought back to life. Ruggedo finds a suitcase that permits traversing alternate realities; he uses it to negate the power of Ozma, Glinda, and the Wizard of Oz.
For good measure, Mrs. Yoop, still in her green-monkey form, also puts in an appearance. So the remaining forces of good in Oz face a triple threat with their strongest assets unavailable to them. Fortunately, the villains fall to fighting among themselves; a blend of traditional Oz magic and new technological magic (ZIP the nymph uses computer-game commands to foil Mrs. Yoop at a crucial moment) wins the day for the side of virtue.
The author exploits a wide range of Baum's Oz characters for his novel, the famous ones — Dorothy, the Scarecrow and Tin Woodman, the Cowardly Lion and Hungry Tiger, and Toto too — and a few of the more obscure as well — Omby Amby, Jinjur, Woot the Wanderer, and Boq the Munchkin farmer. He even brings in the extremely aged mirror image of Queen Zixi of Ix (he calls her Neeuq Ixiz of Xi).
The author brings modern trappings into his story, like computer games and alternate realities; he gives Glinda a crystal ball that functions as a search engine for her library of half-a-million books. Yet he does not neglect traditional literary tactics: Dorothy Anne has a treasure hunt and a word puzzle to solve.