Democracy has been introduced to Equestria. But the alien concept didn't work for the ponies and now Equestria is at an all out civil war between The Solar Empire and The New Lunar Republic.
After three years of endless fighting, everypony is tired and just wants it to end. And now the end might actually be close...
When news of a third party reaches the two princesses, they send their most trusted officers to figure out who they are and if they can help win the war... Twilight, Applejack and Flyttershy from The Solar Empire and Rainbow Dash, Pinkie Pie and Rarity from The New Lunar Republic.
Now the six (former) friends go on their quest to find the strange third party and hopefully bring the war to an end...