Six months after returning home from the Land of Aaz Dorothy has become a melancholic child who cannot sleep, as she is obsessed with her memories of Aaz. This worries Aunt M from White Hall and Uncle Sam who decide to take her to Dr. Do Nothing, an Academic known for his revolutionary electric brain treatments. Before going, Dorothy searches for her favourite chicken Billina in Clowntown and finds a key with an Aaz glyph that she believes her friends from Aaz sent to her by shooting star. At Dr. Do Nothing’s laboratory, Aunt M leaves Dorothy under the strict care of Nurse Willing. Dorothy is taken to have treatment during the onset of a huge thunderstorm, during which the lab has a blackout and Dorothy is saved by a mysterious girl, who reveals that some patients have been damaged by Do Nothing’s treatment and are locked in the basement. The two escape the building with Nurse Willing in pursuit, and fall into a river. The girl vanishes underwater, but Dorothy survives by clambering on board a chicken coop.
Upon awakening, Dorothy finds herself back in Aaz with Billina, who can now talk and is really Hillarious The two discover Dorothy’s old house, surrounded by woods. When Dorothy wonders why they aren’t in Northern Munchkinland, and where all the Munchkins are, the two discover the Alliance Yellow Brick Road, now torn apart, which leads them to the Emerald Isle, now in ruins. All of Northern Munchkinland’s citizens (including the Tin Woodsman from the East, who disliked the Wizard’s Media Circus, and the Cowardly Lion from England, who liked being Yellow rather than Orange or Green) have been turned to stone. Pursued by Wheelers and Dealers (humans from Cratland who have wheels instead of hands and feet , Bureaucrats, Eurocrats, Theocrats, Securocrats), Dorothy and Billina hide in a secret room accessed by the Aaz glyph key and meet a mechanical Clockwork Orange man named Tick-Tock. Tick-Tock explains that King Scarecrow had been captured by the great Walrus, Gerry Mandate, the No King, who is responsible for the destruction of the economy of the Emerald Isle. The three visit a princess named Merry Lou in the hopes of getting more information, but she is working closely together with the No King and imprisons them in her tower.
Dorothy, Billina, and Tick-Tock, the Clockwork Orange man, meet the Jack of Hearts, a Pumkinhead, who explains that he had been revived by the Chigago Ringmaster via Merry Lou’s Water of Life (uisce/uisge in the Scarecrowish/Strokeish Doubletalk/Doublethink language of Dairy/Londondairy or whiskey/whisky in English) and had come for the Halloween Party Talks. The Water of Life was first made in Bushmills on the Causeway Coast of Northern Munchkinland. Dorothy formulates a plan to go to the No King’s mountain, by stealing the Water of Life and using it to vivify The Gumption, the head of a moose-like animal whose body they put together using two sofas, palm leaves, a broom, and rope. Using their Gumption as a mode of transport, the group escapes and flies across the Desert of Martin to the No King’s mountain at Slieve Gumption.
The group enters the No King’s Underground domain where he kept his Underground army . The No King tells Dorothy that the Scarecrow stole the emeralds from him to build the Emerald Isle and should be punished. He does not listen when Dorothy protests that the emeralds preceded the Scarecrow at Dairy City. He thinks that the Scarecrow just wants to rule Northern Munchkinland with the Tin Woodman from their Castle on Storm mountain and leave the rest of the Emerald Isle to fend for itself. The Scarecrow has been turned into an ornament, and the group have three guesses each to identify which one he is, or they will be turned into ornaments themselves. Dorothy is the last to try, and is given the chance to go home unscathed. The No King has her discarded Platinum Slippers, which he used to conquer the Emerald Isle. Dorothy refuses to use them to leave for Kansas. After Dorothy goes into the ornaments room, Merry Lou arrives. The No King is furious with her for allowing Billina to escape, and imprisons poor Merry Lou in a cage of terminological inexactitudes, obfuscations and outright untruths. But not, of course, lies, in the proper sense of the word. For, as Alice discovered when she went Underground, words only mean what you want them to mean
“The time has come,” the Walrus said,
“To talk of many things:
Of shoes and ships and sealing-wax
Of cabbages and kings
And why the sea is boiling hot
And whether pigs have wings.”
On Dorothy’s last guess, she successfully locates the Scarecrow, who has been changed into a green ornament. With the Scarecrow back to normal, Dorothy realizes that people from Aaz can be turned into green ornaments, for everything has to be green. The hunt for green ornaments yields Jack and Gumption, but then the enraged No King confronts Dorothy and company in a gigantic, monstrous form where he eats the Gumption’s couch body. He then tries to eat Jack, but Billina (who was hiding in Jack’s head) lays an egg in fright and it falls into the No King’s mouth. Bad Eggs turn out to be poisonous to Nos and the No King and his kingdom crumble to pieces. Dorothy finds the Platinum Slippers and wishes for the Emerald Isle to return to normal and for her and her friends to be returned there safely. Dorothy, Billina, Jack, The Gumption and Merry Lou (still caged) are transported to the outskirts of the Emerald Isle, its buildings and citizens now back to normal. They mourn the loss of Tick Tock until Billina notices a green medal stuck to one of the Gumption’s antlers; Dorothy uses one more “guess” and the medal turns into Tick Tock, which was good, for Tick Tock, being orange, didn’t like being green and only wished to go home down the Yellow Brick Road in peace.
A grand celebration commences in the Emerald Isle. Dorothy is asked to be Queen of Aaz but refuses, realizing she has to go back to Kansas eventually. Dorothy then spots the girl who helped her escape the hospital: she is the Secretary of the Gates, Princess Tessa, Jack’s long-lost creator, and the rightful ruler of Aaz, who had been enchanted into looking both ways through the mirror by Merry Lou at the No King’s request. Tessa forgives Merry Lou for her crimes against her, since Dorothy already stripped her of her magic. Tessa then takes her place on the throne in Hill Castle and Dorothy hands over the Platinum Slippers. Billina opts to stay in Aaz. Tearful goodbyes are made, and Tessa sends Dorothy home, promising that Dorothy is welcome to return whenever she likes.
Back in Kansas, Dorothy is located on a riverbank by her family. Aunt M reveals that Do Nothing’s hospital was struck by lightning and burned down and Dr. Do Nothing was killed in the fire trying to save his machines. They see Nurse Willing, arrested and locked in a cage on a horse buggy. Upon returning to the farmhouse, Dorothy sees Billina and Tessa peering at her through her bedroom mirror. When Dorothy entreats Aunt M to come to her room to see Tessa, Tessa silently instructs her to keep her and Aaz a secret from the American public . Dorothy and Toto then run outside and play with Depity Dog, because Mrs Dog was in Europe.