Nightmare Moon banished Celestia, only to be defeated by Ahuizotl. Ponykind were made the scapegoats to blame for her scourge. 1000 years they pray for a saviour to deliver them. Anypony will do. Enter the last hope, a pizza delivery dude.
Equestria’s newest baron has just discovered that his new barony is entirely underwater, his new castle is a broken-down old riverboat, and his new subjects are… seaponies. Welcome to the Barony of Fen.