A darkness has taken hold of Ponyville. Foals are disappearing and nopony has any explanation beyond an old nursery rhyme pointing to the legendary Shadowfright. But the Shadowfright is only a story made up to frighten children into behaving. Isn't it? Ditzy Doo isn't so sure and when her daughter becomes one of the missing she, with the help of a strange stallion with an impossible blue box, will face any monster or horror the universe has to offer.