Many years ago, a great pony emerged from the seemingly average Ponyville crowd with five others. These ponies were put to the test in a desperate attempt to save Ponyville from Nightmare Moon, a former princess corrupted by a strange and powerful darkness. When Nightmare Moon was defeated, Princess Luna emerged from the rubble, and the darkness vanished. Many believed that the darkness was gone completely, but Luna forever feared that the darkness would grip her heart and take away her royal self, only to replace it with the hatred that many have worked so hard to remove.
Now; in a final trip to her former prison, Princess Luna must face the creature she fears the most.