Princess Twilight Sparkle writes pony history by opening a portal to another world and making first contact with extra-Equestrian intelligence. Only snag: the portal opens at a pony ranch on Earth.

Nightmare Moon was defeated a thousand years ago, but her legacy remains. Cursed creatures prey on the helpless in the darkness. Beasts and monsters born of nightmares. But the Apples maintain a sacred vigil. They are the Slayers.

Being awesome has unintended consequences for Rainbow Dash, as a windigo she has brought to existence needs tender loving care.