Long ago, when the world was young, ancient and powerful beings roamed the world. Primitive tribes of mortal creatures gave worship to these beings, these gods, and great was the suffering the felt at their hands. Wars were fought, plague and famine would grip the land for years at a time. Friends murdered friends and family, and the races did great harm unto themselves and to others.
But all that changed with the birth of the Sun and Moon, Celestia and Luna. Together the two fledgling goddesses, with the power of the Elements of Harmony, made war against their dark breathern destroying the cults and finally banishing them from the world either by locking them away in stone, or destroying them completely and utterly that not even their names could be recalled. Thus did this end the time of Chaos, and did the time of Harmony begin.
But now, thousands of years later something begins to stir. An old enemy makes one last return, and one final push to bring chaos to the lands and perhaps to bring about his rebirth. The only thing to stand against this tide are six ponies, the bearers of the Elements, and one human man whose origins even he does not full know.