Everyone knows that Celestia went to the sun when Nightmare Moon came back, or did she? What if she Celestia made a friend in another world during her short term banishment, a friend that really gets her and not the princess she has to be?
There really is not much to say, except I am here for the same reason I write on Fanfiction. I want to entertain you with my writing, not just detail it but make you feel that you are in the story.