This story is a sequel to If You Had To Choose
Unable to find Princess Luna's hidden Elements in time, Princess Celestia is forced to confront her sister and banish the Nightmare at the end of their battle in the Everfree Castle with only half the Elements and half the power needed to seal Nightmare Moon away.
So what if she did. Where would Nightmare Moon go?
(Note: Not required to read the prequel to read this story.)
An entry in the Chaosverse