(Based on a pic by johnjoseco in deviantart.)

When Twilight's friends catch up to her during her square-off with Nightmare Moon, they all manage to awaken the Elements of Harmony slumbering within, and they defeat the Nightmare once and for all. Princess Celestia has been released from wherever she has been sealed, and she and her little sister can rule Equestria together again. Right?

Well, there's a twist. Luna's no longer a PRINCESS, per say…

Taking up the name of Prince Osiris, he vows to amend for his past sins as he resumes his reign over the Equestrian night. But how is the former moonlight maiden to contend with an elder sister who dotes excessively on the brother she secretly yearned for, the horde of female admirers that grows by the day, and the general gender norms imposed upon stallions by Pony society?