It’s Cookie Monster’s first day at a terrifying new school and she’s not feeling good about leaving her old lovely life. Little does she know that this isn’t any normal school, not at all. In this school her teacher is a witch, the librarian is a skeleton and what is wrong with the Principal and his evil laugh? After being punished with slime, bullies, custard pies and being chased by hippos Cookie Monster needs to find a way to get this Horror School closed down. With the help of her friends she comes up with a plan, but with Halloween approaching the ghosts are out to stop her and she’s going to have to summon all her bravery to defeat the maniac Principal Brown.