Monster High: Ghouls Rule unearths an old conflict between "Normies" and monsters - and things are about to get scary. For years, students at Monster High were warned that Halloween was a night to stay inside and avoid conflict at all costs. But Frankie and her friends discover that ghouls and "Normies" once loved to spend the holiday together. The ghouls decide to turn back the clock and use the night to celebrate their individuality and show that it's okay to "Be Yourself. Be Unique. Be a Monster!"