The fanfics take place in a very elaborate version of what a Disney Multiverse could be like: it has its inner balance, each world being a new branch to a metaphorical "tree" of which the "Center World" is the trunk. The Center World is a medieval-fantasy-themed utopia where the classical characters such as Mickey, Donald, Goofy, Clarabelle or Yen Sid live. To study other worlds, Yen Sid, who is King Mickey's adviser, has created the Doorway, a magical doorway that allows people to travel to other worlds, and the Viewing Basin, in which Yen Sid can see what happens in various worlds and write it down in the Book of Legends that he created.
The story begins when Yen Sid brings the Magic Mirror back from Snow White's world, where it had been abandoned carelessly in Queen Grimhilde's castle after her demise. The Mirror then proceeds to pronounce a prophecy: "a great horned evil will unbalance the worlds, and the heroes need to gather in one place to keep darkness at bay". But soon, Pete steals the key to the doorway, hoping to find a way to take revenge on Mickey in another world. He ends up in Prydain, where he accidentally revives the Horned King, who, made aware of the other worlds, decides to conquer them. He is now merged with the power of the Black Cauldron, which allows him to bring the dead back to life in a wave of his hand; which he does, on any Disney Villain he can find. Once he has gathered the villains, he redistributes roles: Scar attacks Cinderella, Gaston attacks Simba, Queen Grimhilde attacks Aurora
Soon, the worlds lose their precious balance, and things start to revert to the way they were before the stories happened: Ariel goes back to being a mermaid, and the Prince turns back into the Beast. Meanwhile, the Horned King is perfectly aware of the danger of the worlds being destroyed, but it suits his great purpose: he wants to be a god, and once the worlds are destroyed, he thinks he'll be the one to rebuild them to his own image. Mickey, Donald and the gang, realizing the threat of the King, start to gather the heroes of every world in their own world. But since the Doorway is now unusable because of the lost balance, they have to use the more archaic portal spell, which heavily drains on the user's life-force. And Yen Sid's health is deteriorating
Thanks to positive reviews, technomizer wrote two sequels:
- In End of Worlds A Disney Crossover Sequel, a mysterious enemy known as the Master of Worlds, and who claims he's working for a greater good, captures Alpha Beingsnote to use their magic essence to merge all the worlds into one, to remove the problems caused by the risk of unbalancing the worlds. The story is told from the point of view of Merida, from Brave, who later returns as the hero of the next story. The Blue Fairy and Yen Sid finally decide to call Mary Poppins for help, with her being portrayed as one of the most powerful Alpha Beings in existence, that even Chernabog respects. Word of God has it that she's treated as "the Disney equivalent of the Doctor".
- In The Final Adventure A Disney Crossover Finale, the Master of World has finally succeeded in uniting the worlds together into a single one. Thanks to a potion that Mary Poppins made her drink before the merging, Merida still remembers the original worlds clearly, but a Cosmic Retcon has changed the history of the now single World and of its characters, who however retain small glimpse of their former lives in dreams. The problem is that the interference of the stories has changed the course of the heroes's history: captain Jack Sparrow freed Aladdin from prison before he met the old prisoner who led him to the lamp, Shan Yu, thanks to external help, as conquered China and made it into the Hun Lands, and Minnie never married Mickey who remained captain of the musketeers. Merida finds the Master of Worlds masquerading as Lord Arawn, king of Prydain, but discovers he's only a pawn on the chessboard of another, far more powerful Master
Disney's War provides examples of:
- A God Am I: The Horned King had already a bad case of that in his debut appearance except that here he actually does it, and upgrades to being the Horned God at the end when he merges with Chernabog.
- Big Bad: The Horned King, who tries to conquer the whole multiverse.
- Curiosity Is a Crapshoot: Invoked by Taran about Yen Sid, as he argues that had Yen Sid not invented the doorway, none of this would have happened. Surprisingly, Mary Poppins eventually agrees with him in the very last chapter of the last story, and consequently closes any mean of traveling from one world to another.
- Full-Name Basis: In "The Final Adventure", the third story in the series, Mary Poppins insists on being called Mary Poppins; she can accept "Mary" from close friends like Bert, but won't let anyone call her "Mrs Poppins", "Mrs Mary Poppins" or, worst of all, "that nurse".
- Great Big Book of Everything: The Book of Legends, in which Yen Sid wrote the detail of every story of every world. The villains later steal it to know who they must recruit in which world.
- Hijacking Cthulhu: In a pretty straight example, the Horned King takes control of Chernabog's body and powers during the climax of the first story. When the Horned King is defeated, Chernabog is restored to his regular self.
- Only in It for the Money: The Pete family in the sequel seems to help the Master of Worlds only because he promised them fantastic riches should he succeed, which come in the form of ponies for Pistol, Pete's young daughter.
- Pragmatic Villainy: Surprisingly, Chernabog is treated that way; he agrees to help the heroes defeat the Horned King and the other villains because he knows that conquering the multiverse would be a bad idea, as it would disturb the balance of the worlds, change the laws of magic forever and thus possibly weaken him. (Which does happen in the third story.)
- Reality Warper: Alice is portrayed that way, as she can make anything she imagines come true.
- Utopia Justifies the Means: Invoked by the Master of Worlds when he kidnaps Rapunzel, Ray, the Spring Sprite and a few more.
- Walking Spoiler: In the third story, it is not revealed that the "Master of Worlds" is actually Alice from Alice in Wonderland, turned insane and evil until pretty late in the story, and his identity was already a mystery in the previous story, End of Worlds. The origin of his powers was also pretty mysterious, but all makes sense once we know that "he" is actually Alice, who in the context of the series is one of the most powerful RealityWarpers in existence.
- Well-Intentioned Extremist: The Master of Worlds, in the sequel, tries to pass as one, thanks to his "Utopia Justifies the Means" reasons (see this entry). The Reveal that there is another Master who is The Man Behind the Man to the Master of Worlds, and that this person is Alice turned evil seems to shift the Well Intentioned Extremism to Alice. However, the second Reveal that a figment of the Horned King's mind had been controlling Alice the whole time, and that it was a very elaborate Evil Plan to conquer the World negates any "well-intentions" seen in the whole story.
- You Have Outlived Your Usefulness: Said almost verbatim by Evil!Alice to Arawn after he let the heroes sneak into her bedroom to try to assassinate her.Evil!Alice: "While youve been ever so helpful to me, Arawn, so loyal, Im afraid your usefulness has ended."