Spots 
A sudden tremor fractures the California earth beneath Hugson's Ranch, dropping Dorothy Gale, her cousin Zeb, Jim the old cab-horse, and Eureka the kitten into a dark, bottomless abyss. As they tumble harmlessly through subterranean space, the rules of surface gravity give way to a gentle, floating descent.
The travelers land in the realm of the Mangaboos, where transparent glass buildings sparkle beneath cold, color-shifting suns. Lacking hearts and human warmth, the plant-like inhabitants view the flesh-and-blood strangers with cold suspicion rather than hospitality.
A runaway hot-air balloon descends into the Glass City, delivering the former Wizard of Oz equipped with nine tiny piglets and his familiar tricks of sleight of hand. Reunited with Dorothy, he uses minor humbug magic to temporarily intimidate the hostile Sorcerer of the Mangaboos.
Mangaboo society functions without birth or natural death, growing new citizens on vines like garden produce. Because these vegetable people lack sympathy and feel no pain, they judge meat people as unwanted intruders deserving execution in the black pit.
To ease their captivity, Dorothy adopts a miniature piglet from the Wizard's collection, bestowing a name upon the creature to claim it as a companion. The act highlights the contrast between human affection and the unfeeling nature of their plant-based captors.
The ruler of the Mangaboos rejects the Wizard's tricks and demands the strangers be carved into vegetable scraps. Realizing reason cannot move beings without hearts, the party resolves to escape deeper into the earth before the new Sorcerer ripens.
Fleeing through subterranean caverns, the companions ascend black stone passageways into absolute darkness. Without light or clear direction, Jim the cab-horse pulls the buggy onward, relying on animal instinct to navigate the inner world.
The travelers emerge into a lush countryside where invisible fruit trees bloom beside silver streams. Beautiful landscapes turn hazardous when invisible creatures dwell everywhere, hiding potential danger behind deceptive tranquility.
Monstrous invisible bears attack the group, detectable only by rustling grass and heavy footsteps. Zeb and Jim fight fiercely against unseen claws until the Wizard uses clever trickery and glass spectacles to help reveal the creatures' whereabouts.
High on Pyramid Mountain, an eccentric solitary inventor named Rustle weaves rust-proof wire and hair into strange household goods. Living alone in a cave, he offers hospitality and directions, proving that odd isolation can foster harmless generosity.
Wooden winged creatures with silent, expressionless faces inhabit a colorless volcanic landscape. Lacking speech and hearing, these relentless gargoyles attack in silent swarms, forcing the travelers to fight their way through a completely soundless battle.
Cornered in a dark mountain cavern, the group encounters motherless baby dragons trapped behind iron bars. Though small, the scaly beasts threaten the party with fiery breaths, emphasizing that danger underground takes many distinct biological forms.
Trapped without escape deep inside the mountain, Dorothy wishes upon Princess Ozma of Oz to observe them through the Magic Picture. Recognizing Dorothy's plight, Ozma activates the Magic Belt to transport the exhausted party directly to the safety of the Emerald City.
Sudden arrival in the radiant capital brings immediate relief, rich feasts, and warm reunions with old friends like the Scarecrow and Tin Woodman. The contrast between subterranean horrors and Oz's bright utopian order restores hope to the weary travelers.
Accused of eating one of the Wizard's nine tiny piglets, Eureka faces a formal court trial presided over by the Woggle-Bug. The legal proceedings explore justice, evidence, and instinct, demonstrating that Oz maintains moral accountability even for minor pets.
Eureka reveals she had hidden the missing piglet as a joke, proving her innocence of murder while exposing her mischievous nature. With peace restored and all companions accounted for, Zeb and Jim return to California while Dorothy stays safely linked to Oz.
Discover a subterranean journey through strange underground worlds before returning to the magic of Oz.