The Wizard of Oz opens with a spirited young girl named Dorothy living on a farm with her aunt and uncle, three farmhands, and her loyal dog, Toto. Dorothy and Toto's connection is tested by a cranky and powerful neighbor, Miss Elvira Gulch, who wants to have the dog "destroyed" for biting her once. Afraid of what Miss Gulch will do to Toto, Dorothy runs away with Toto in tow and happens upon the "psychic," Professor Marvel, who looks in his crystal ball and tells her that she ought to return home, as her Aunt Em is worried sick about her well-being.
As Dorothy is returning a home, a great tornado has begun, and Aunt Em, Uncle Henry, and the farmhands have taken refuge in the cellar before Dorothy has returned. In the house, Dorothy is knocked unconscious by a window that flies out of its frame. The house is picked up by the cyclone and dropped in the land of Oz, right on top of the Wicked Witch of the East.
When Dorothy emerges from her house, she finds herself in Munchkinland, where she is met with adulation, as a hero who killed a wicked and unjust witch. Unfortunately, the Wicked Witch of the East's sister, the Wicked Witch of the West, is upset about the death and is determined to get vengeance on the innocent Dorothy. When Dorothy announces her intentions to return to Kansas, the Good Witch of the North, Glinda, sends her to the Wizard of Oz, whose palace, in the Emerald City, is a ways down the yellow brick road. Before sending her on her way, Glinda bestows Dorothy with the Wicked Witch of the East's ruby slippers, advising her never to take them off.
A little ways down the yellow brick road, Dorothy encounters a Scarecrow, who complains about not having a brain. Dorothy invites him to join her on her journey to the Wizard of Oz, suggesting that perhaps there he could get a brain. As they go down the yellow brick road, they get into a scuffle with some cranky apple trees, before meeting a rusty Tin Man, who wants a heart more than anything in the world. Dorothy invites him to come along on their journey as well, and they make their way into a dark forest. In the forest, they encounter a Lion who, in spite of his initially frightening affect, reveals that he is terminally cowardly. He joins the group too.
Just when the group is about to reach the Emerald City, the Wicked Witch of the West carpets a giant field in their way with poisonous poppies. On their way through the field, Dorothy, the Lion, and Toto all fall into a deep slumber, but Glinda sends snow to kill the poppies and wake them up. They continue on to the Emerald City, a giant green urban utopia, where they all get makeovers.
They go to visit the Great and Powerful Oz, a disembodied and rather intimidating head, who instructs them to obtain the Wicked Witch of the West's broomstick before he can grant them their wishes. Disappointed, the group heads into a haunted forest to find the Witch. In the middle of their journey, the Witch's army of flying monkeys come and kidnap Dorothy and Toto, leaving the Lion, Tin Man, and Scarecrow behind.
At the Witch's castle, the Witch wants Dorothy's ruby slippers. Toto manages to escape from the castle and go to the Lion, Tin Man, and Scarecrow to tell them about Dorothy's whereabouts. When the Witch tries to take Dorothy's shoes, she is shocked by a strange power that prevents her from taking them unless she kills Dorothy. Overturning a giant hourglass, the Witch tells Dorothy that she will be back shortly to kill her. Dorothy is despondent, but pretty soon, her companions sneak into the castle disguised as guards and set Dorothy free from her locked chamber.
As they start to leave, the Witch and her guards corner the group. Before killing Dorothy, the Witch plans to hurt her companions, and she lights the Scarecrow's arm on fire. Trying to save her friend, Dorothy throws a bucket of water on the Scarecrow, and some of it gets on the Witch, who screams and begins to melt. Dorothy unintentionally kills the Witch, takes her broom, and returns to Oz.
When they go to visit the Great and Powerful Oz again, he tells them to visit him the next day, and the group is deeply disappointed. Just when it seems like they have no hope, Toto pulls back a curtain nearby, revealing the man behind Oz, an anxious and mysterious man who is posing as a magical and powerful wizard. After explaining that he is just a simple Kansan man who came to Oz via hot air balloon many years ago, he tries to help them get what they came for. He tells the Scarecrow that he's always had a brain, the Tin Man that he already has a heart, and the Lion that he is brave. Oz then offers to take Dorothy home in his hot air balloon.
As the hot air balloon is about to leave Oz, Toto jumps off it, and Dorothy must follow him. The balloon floats away and Dorothy fears she has no way to return home. Just as she begins to worry, Glinda appears and tells her that if she clicks her heels together and imagines home, she will return. Dorothy clicks her heels, says "There's no place like home," and is returned to her bed in Kansas.
