It's been three thousand years since the world was plunged into eternal twilight. By now, the two Princesses of the Sun and Moon have become nothing more than a legend. Just one of many tales that mothers told their foals to help them get to sleep at night. Surely, nopony could possibly believe that the sun ever sat at the center of the sky or that the moon could wax or wain. But when two earth ponies stumble across an ancient artifact, the line between legend and history begins to blur. It's time for a new legend to be born.