The story begins with Azula and Kevin 11 doing performing an important task for one of the Orgs members as they drop by a laboratory being run by Dr. Eggman and Dr. Animo. While there, the two villains witness a massive lifeless robot which was found in another world. As Eggman and Animo explain the origins of the Fabrication, Azula starts to feel weird around it. Another subplot involves Mr. Bun and his candy army being accepted into the Organization and creating an elixir that would turn them all into monsters. Back at the lab, Dr. Animo foolishly gives life to the Fabrication at the cost of his life. Unable to stop it, Eggman sounds the alert before he too meets the same fate.
While Mr. Bun is at another world, the Fabrication had already built hundreds of machines that run rampant through the castle killing hundreds of villains. Azula and Kevin 11 get rescued by the Huntsman and follow him to an emergency bunker. In a third subplot, Oogie Boogie and the Other Mother (who are in love with each other) do their best to hold off the monsters to which Oogie is injured in the process. In the emergency bunker, Azula and Kevin 11 are forced to share a room with the Huntsman, Ozai, and Vilgax as they try to come up with a plan. Vilgax however is less than thrilled and goes out on his own to which he is quickly injured and captured. Oogie Boogie and the Other Mother find Vilgax in peril and follow him to wherever the machines are taking him. Kevin 11 and Azula run towards the Fabrications chamber while Ozai and the Huntsman hold off other machines in their way. When they make it, they learn that the Fabrication is actually stealing villains souls with the help of a special talisman. Even Maleficent appeared to have fallen to the machines. Kevin and Azula along with Oogie and the Other Mother plot to destroy the robot, but their cover is another robot attacks. When Kevin gets in trouble, Azula stands paralyzed in fear unable to help prompting Ozai and the Huntsman to help. The Fabrication spots them all and takes the lives of the Other Mother, Ozai, and the Huntsman. However, Oogie was able to hold the machine off long enough for Kevin and Azula to escape.
After they find shelter, Kevin demands an explanation as to why Azula couldn't help him. What follows is a short flashback to when Azula was sent on a mission and was immediately attacked by robots. Since that day, she had been afraid of machines. As the fire princess breaks down, Kevin cheers her up by saying his biggest fears. Once they get their act together, they concoct a plan to beat the Fabrication once and for all. Unfortunately, Kevin's life is taken away too. Before Azula could be beaten, Mr. Bun and his candy monsters arrive mutated from the effects of their magic elixir and start ripping the robot army apart. Seeking her chance, Azula runs to the rooftops where the Fabrication follows. After an epic fight, Azula grabs the talisman away and mercilessly destroys the Fabrication. With her victory ensured, she free the souls of all the dead villain saving the entire Organization.
We then cut to Halloween night where everyone is celebrating. Oogie Boogie and the Other Mother engage in romantic conversations, Mr. Bun is upset over wasting his magic elixir before he could test it on Underfist, and Azula proves to Kevin that her fear of machines is gone for good. The story ends with GIR rolling by saying "Happy Halloween! And a Happy New Year!"