[Ignores Season 3 finale]
In a world full of ponies in the year of 1982 (in our time, it would be year 2012). They were the only creatures to be dominant and sentient. Without anything to oppress them, they simply remained divided since the first 3 tribes. Over the years, the migration of empires and empires had brought new cultures and political divisions throughout the planet. Disuniting them even more. Now, the countries are preparing a war once again. A Cold war world leads to World War 3, A war of Capitalism vs. Communism.
But when the Mane 6 gets thrusted into this world and into many different countries, they must find a way to get back... and perhaps... unite the world into a different but greater Equestria.
But being on both sides would give some complications.