Dorothy Gale is a young, aimless nurse living with her adoptive family of Aunt Em and Uncle Henry on their farm in the tiny town of Lucas, Kansas. Shortly before her birthday, Dorothy is contacted by Karen Chapman, the biological mother who gave her up 20 years ago under mysterious circumstances. Aunt Em encourages Dorothy to reach out to Karen, and as a wicked storm gathers on the horizon, Dorothy heads for Karen's trailer. She discovers a dead police officer in the trailer, with an injured Karen taking refuge in the storm shelter. Dorothy is confronted by another officer who draws his gun, but a tornado sweeps him up with just enough time for Dorothy to dive into a police cruiser for safety. The twister transports Dorothy, a police dog, and the cruiser to the Land of Oz, and on arrival Dorothy accidentally runs over the Wicked Witch of the East before crashing into a tree.
Taken to a Munja'kin tribal village led by chief Ojo, Dorothy is warned the death of a Cardinal Witch like East will make her a target for the Wizard and other Cardinal witches, Glinda and West. As such, Dorothy is to be banished from Munja'kin territory. Ojo leads Dorothy through a mountain, past the Prison of the Abject (where East imprisoned non-Cardinal witches (including Ojo's wife) after the Wizard banned the use of magic in Oz), and sends her on her way down a brick path.
Meanwhile in the Emerald City, the Wizard has been informed that one of his steampunk flying monkey drones recorded an object falling from the sky. The Wizard believes this a sign of the return of "The Beast Forever," a powerful entity that has attacked Oz in various guises throughout the years. He seeks the aid of Mistress West, another of the Cardinal witches, who runs a brothel in the Emerald City now that the Wizard has outlawed magic.
Dorothy travels towards the Emerald City with the police dog at her side and meets a crucified amnesiac outside a burnt out town. She rescues the man and names Lucas. The two are confronted by the resurrected East, but Dorothy fools the witch into shooting herself in the head using a gun Dorothy had taken from the police car. The Wizard dispatches his soldier Eamonn to find and kill Dorothy.
- Ban on Magic: The Wizard has outlawed magic practiced by anyone other than the Cardinal Witches, even going to far as to enlist East in creating an inescapable prison for non-Cardinal witches.
- Beauty Is Never Tarnished: After the tornado throws Dorothy's car at East, neither of them look much the worse for wear, even though East went up over the hood and Dorothy got smacked in the face with the airbag after the car flipped a couple times. There's a little trickle of blood, but that's all.
- Boom, Headshot!: Dorothy manages the impressive feat of landing a bullet between the eyes of her target without even holding the gun. She tricks East into pointing the pistol at herself and pulling the trigger. When the other witches examine East's body, they wonder how someone carved a perfectly round hole into her forehead and why anyone would do so.
- Car Fu: Instead of a house that falls on the Witch of the East, it's a police car. Dorothy was transported to Oz in a police cruiser, and when the cruiser is deposited in Oz she accidentally floors it, running over the witch of the East.
- Do Not Touch the Funnel Cloud: Although there's wind and debris whipping around Karen's trailer, both Dorothy and the police officer are able to stand outside and argue until the funnel cloud barrels down on them and scoops up the officer. With the funnel cloud less than 50 feet away from her, Dorothy is able to duck into the remaining cruiser to protect herself from the storm — at least until the funnel cloud hits the car, at which point that gets scooped up too.
- A Dog Named "Dog": This incarnation of Toto takes his name from the Munja'kin word for "dog." Dorothy didn't get the chance to learn the dog's name before they were swept up in the tornado, and she figures "Toto" is as good a name as any for a dog.
- Happily Adopted: Downplayed with Dorothy — she loves Em and Henry, who gave her as good of an upbringing as they could, but still calls them Aunt and Uncle. She's hesitant to get in contact with her birth mother, and it takes Em's encouragement for Dorothy to take the plunge.
- The Hero's Birthday: Dorothy took the opportunity of her birthday to go visit her biological mother, and the plot gets kickstarted when a tornado shows up and whisks Dorothy away to Oz.
- Mythology Gag: There's a rainbow sun-catcher in the Gales' kitchen window, referencing Judy Garland's famous solo "Somewhere over the Rainbow" from The Wizard of Oz.
- Torture Is Ineffective: The Munja'kin water torture for Dorothy proves to be ineffective when the truth she tells doesn't give them the answers that they want.