The borderlands are not a location in Equestria so much as a state of mind. The border between civilization and barbarianism; sanity and insanity; survival and death. After a century the Manesville Stable had to open up. The world they entered was far rougher than the one their grandparents had left behind.
The Overmare and Overcow made alliances with several surrounding communities of survivors and blended their populations together to form the Co-op, a bastion of hope and survival. For the past century they have flown under the detection spell, but events out East, as well as in Hoofington have forced their hooves.
It is here that we find Mollygirl, an earth pony mare, and her squadmates in the Co-op Guard as they discover and fight for those they love and their Co-op's future as well as that of a fledgling NCR. Not all heroes fight alone, even though they may try to. When the cost begins to take its toll, it is time to remember the Co-op Guard Motto. For Friends, For Family, For Herd.