You know the story of Nightmare Moon. Or so you think. What many do not know is the story before she was banished, My name is Shadow Moon but everypony over the past thousand years have called me Twilight Sparkle and this is my story.
Princess Luna, struggling with the loss of the one closest to her, attempts to re-integrate into society after her return from her imprisonment on the moon. All the while, she fights to cope with a growing envy and burning hatred for her sister.