It's the night before Christmas and Phineas, Ferb, and the rest of the gang are filled with holiday cheer, but little do they know that Santa and his elves were told that every child in Danville is on the naughty list.
Phineas and Ferb construct a haunted house to scare away Isabella's hiccups, but their werewolves, vampires, and other frights might turn out to be too scary.
Dr. Doofenshmirtz builds evil creations, comes up with bizarre inventions, opens a school for budding scientists, and plots to conquer the tri-state area and defeat Agent Perry the Platypus.