Felix’s school is once more plagued by a ghostly presence, but this time it’s not the mischievous yet harmless spirit of the school’s founder, Otto Leonhard. Instead, it’s the despised and long-deceased Director Hulda Stingbeard. A twist of fate revives the once-shrunken and skeletal former principal. Upon her return to the living world, she nearly overpowers Otto Leonhard, successfully miniaturizes Dr. Schmitt-Gössenwein and Felix’s parents, and seizes control of the school. It falls to Felix, Ella, and their friends to take action, restore order to the school, and return Dr. Schmitt-Gössenwein and Felix’s parents to their normal size.