A long time ago, Celestia banished her sister, Luna, to the moon after she lost control of herself and became Nightmare Moon. A thousand years later, the mare on the moon returned. Twilight Sparkle and her companions travelled through the Everfree Forest in an attempt to stop her, but the evil princess smashed the Elements of Harmony to nothingness. Having destroyed the Elements, Nightmare Moon runs free. She is the new ruler. There will be eternal night.