Inspired by KnightMysterio's take on the Nightmare-Timeline in the story Context
The Princess of the Sun has fallen, the Queen of the Night now takes her place.
To the surprise of many, Nightmare Moon isn't evil. Or insane for that matter. She is attempting to be a queen that can properly rule a nation she has not seen in a thousand years. Some will try to aide her, others will attempt to thwart her, but the Wrath of the Night is something not to take lightly.
However, Celestia may have made a mistake in letting Luna fade from history and the only mention of Nightmare Moon become a demonized fable- no one would take that very well in her place.
Features: Twilight reluctantly helping a Sane and Noble NMM, curious and confused guards, and ponies being reminded of their lost history.