In the magical land of Equestria, harmony between ponies is maintained through the power of friendship. The kingdom is ruled by the wise and ancient alicorn ruler Princess Celestia, who once ruled alongside her younger sister Princess Luna. Long ago, Luna became corrupted by jealousy and transformed into Nightmare Moon, plunging Equestria into eternal night. To protect her kingdom, Celestia used the powerful Elements of Harmony to banish Nightmare Moon to the moon for one thousand years.