In a last act of defiance, King Sombra not only dragged the Crystal Empire with him to his thousand-year imprisonment, but the Elements of Harmony as well. And so, with the rise of Nightmare Moon, the course of history was forever altered.
A thousand years later, on the Eve of Hearth's Warming, a certain young dragon is tasked with overseeing some of the preparations for the upcoming celebration, with a strange addition to the list; make a few friends. He can't imagine why; it's not as though the fate of Equestria depends on it.
But neither could he imagine the return of the dark king on that very night, and never would it cross his mind that he would soon embark on a journey to the north to stop him, with a group of strangers by his side.