Equestria was threaten by an unknown dark force, and even a powerful goddess like Celestia is helpless to stop the darkness from spreading. Sooner or later, the darkness will cover this beautiful land, just like a hundred thousand years ago. If Equestria try to fight it alone, the kingdom won't stand a chance. But they were not alone. From the high heaven, an angel was sent to Equestria to protect them from the war between the immortal and learn a valuable lesson about friendship, and even love.