There really is no excuse for forgetting something as important as a hoof-written law. But Celestia forgot. And now, a thousand years after she wrote it, a law comes into play mandating that Celestia take a two-month sabbatical from her duties as Princess of Equestria.
So what happens when she has to step down for a couple months and leave Luna by herself in the bloody gladiator ring that is Equestrian politics? What happens when Celestia has to disguise herself and mingle with the populace of Ponyville without them knowing?
The short answer to that would be "a string of hilarious chance encounters, sisterly banter, romantic mishaps, and a political coup that was decades in the making."
The long answer, of course, is this story.
Rated Teen for swearing and sexual humor.
Cover image is by enma-darei