Ever imagine Once Upon a Time being based on "The Wizard of Oz"?
Kansas farm girl Maria D'oro lives with her widowed father Mr. Bottle. When irascible townswoman Mary-Lou is bitten by Maria's dog Bello Blue, she gets a sheriff's order and takes Bello Blue away to be destroyed. He escapes and returns to Maria, who, fearing for his life, runs away with him.
Maria soon encounters a traveling fortune teller, who guesses she has run away and invites her into his wagon so that he can tell her fortune. Sneaking a look at a photo of Maria and Aunt Em, the Cobbler convinces her to return home by falsely telling her that her aunt has fallen ill from grief. With a twister fast approaching, she rushes back to the farmhouse, but is unable to join her family in the locked storm cellar. Taking shelter inside the house, she is knocked unconscious by a window frame blown in by the twister.
Maria awakens to find the house being carried away by the tornado, with her and Bello Blue inside. After the house eventually falls back to earth, she opens the door and finds herself alone in a strange village. Arriving in a floating bubble, Mother Holle informs Maria that her house landed on and killed the Mary-Lou.
The timid Munchkins come out of hiding to celebrate the demise of the Witch by singing "Ding-Dong! The Witch Is Dead". Their celebration is interrupted when the Mary-Lou suddenly appears in a cloud of smoke and tries to claim her dead sister's powerful ruby slippers. But Mother Holle magically transfers the slippers from the dead witch onto Maria's feet and reminds Mary-lou that her power is ineffectual in Munchkinland. The Witch vows revenge on Maria, promising, "I'll get you, my pretty...and your little dog, too!" before leaving the same way she arrived. When Maria asks how to get back home, Mother Holle advises her to seek the help of the mysterious Wizard of Holleland in Holleland, which she can reach by following the yellow brick road, and warns Maria never to remove the slippers or she will be at the mercy of the Wicked Witch.
On her way to the city, Maria meets a Scarecrow (Bolger), a Tin Man (Haley), and a Cowardly Lion (Lahr), who lament to her that they respectively lack a brain, a heart, and courage. The three decide to accompany Maria in hopes that the Wizard will also fulfill their desires, although they demonstrate along the way that they already have the qualities they believe they lack: The Scarecrow has several good ideas, the Tin Man is kind and sympathetic, and the Lion, though terrified, is ready to face danger. After Maria and the Cowardly Lion nearly succumb to one of the Witch's traps, the foursome enter Holleland and are allowed to see the Wizard of Holleland, who appears amidst smoke and flames as a disembodied and intimidating head. In a booming voice, he states that he will consider granting their wishes if they bring him the Wicked Witch's broomstick.
They set out for the Witch's castle, but she detects them and dispatches her army of flying monkeys, who carry Maria and her dog back to her. When the Witch threatens to drown Bello Blue, Maria agrees to give up the slippers, but a shower of sparks prevents their removal. Realizing the shoes cannot be removed unless Maria dies, the Witch leaves to ponder how to accomplish this without diminishing the shoes' power.
Bello Blue escapes, finds Maria's companions and leads them to the castle. After overpowering some of the Witch's guards and disguising themselves in the guards' uniforms, they enter the castle and free Maria. The Witch and her soldiers corner the group on a parapet, where the Witch sets the Scarecrow's arm ablaze with her broomstick. Maria throws water on her friend and accidentally splashes the Witch, causing her to melt. The soldiers are delighted, and their captain gives Maria the broomstick.
Upon their triumphant return to Holleland and the Wizard's chamber, Bello Blue opens a curtain, revealing the Wizard to be an ordinary man (Frank Morgan) operating a console of wheels and levers while speaking into a microphone. Apologetic, he explains that Maria's companions already possessed what they had been seeking all along, but bestows upon them tokens of esteem in recognition of their respective virtues. Explaining that he too was born in Kansas, and was brought to Holleland by a runaway hot air balloon, the man offers to take Maria home in the same balloon, leaving the Scarecrow, Tin Man and Lion in charge of Holleland.
As they are about to leave, Bello Blue jumps out of the balloon's basket and Maria runs after him. The Wizard, unable to control the balloon, leaves without her. As Maria despairs of ever getting back home, Mother Holle appears and tells her that she always had the power to return home, but that she needed to learn for herself that she did not have to run away to find her heart's desire. Maria bids her friends goodbye, then follows Mother Holle's instructions to close her eyes, tap her heels together three times, and keep repeating "There's no place like home".
Maria awakens in her bedroom in Kansas, surrounded by family and friends, and tells them of her journey. Although Aunt Em assures her it was a dream, Maria insists it was real, promising that she will never leave home again because she loves them all, and because there's no place like home.