A princess stands at the top of Canterlot Castle's tallest tower. She is consumed with wanderlust, and chased with images of the past. Her most infamous mistake–her transformation into the wicked Nightmare Moon–is inconsequential, now. She has put it behind her, and learned from the experience. But older wounds still scar her heart, and an unfamiliar land makes her distant. She yearns to be away… to be before…

A princess sits on a velvet cushion, in Canterlot Castle's throne room. She wears a mask of peaceful contentment, but underneath it, she is worried. Whispers of spies in the capital have reached her ears, coming not from any of the neighboring countries, but from within Equestria itself. Her sister is back, safe and whole, but she feels that she was responsible for her banishment to begin with. Guilt claws at her chest, and wounds that have festered for a thousand years will soon be reopened.

Tucked away in a hidden mountain pass, a village resides. It has gone undetected for a millennium, since its founders sought out a secure place to hide. Its residents are fiercely loyal to the Princess of the Night, and now that she is back, they can finally strike down the Princess of the Day and restore Equestria's true ruler to the throne. A crime committed long ago–the neglect and banishment of a diarch, by a diarch–will soon come to justice.