Nightmare Moon is tormented every Nightmare Night during her imprisonment on the moon, but now her powers are returning, and she intends on using them to exact her revenge.
In the frozen north of the world the lost realm of Equestria sits, bathed in the pale moonlight of its eternal moon. But on this day a lone figure has trudged across the border. Perhaps the long night is coming to its end.
Welcome to 1,000 years B.S. (Before Starlight). This is a time when Luna's life is great. Everypony is happy and nopony is possessed by night demons. Nothing in the six months from the Winter Solstice to the Summer Solstice could change that, right?