Nightmare Moon has returned, and a mishap in Twilight's Spell transforms her and Celestia into mere fillies. With no way to turn back, they must find a way to return to their former selves. Two enemies are forced to join hooves and possibly settle their differences.

Nightmare Moon is rather unamused and has no choice, being powerless now, but to roll with the punches.

Cover art done by FairySearch on Deviantart