When King Sombra is defeated b the main six, his soul still remains. That very soul reenters Equestria as a foal, a filly to be exact. What will happen to the peaceful world, when it's biggest menace is reborn?
What happens when a Changeling and a Bat-pony have foals? A Batling. Not even the princess of the sun know what these hybrid creatures are. When Luna explains them to Celestia, the solar god wants to know more. Aldatu, a Batling, just wants to escape