A thousand years before Twilight Sparkle's birth, King Sombra has conquered the Crystal Empire and enslaved its citizens. From there he turns to the land of Unicornia, only for a single unicorn princess to escape his clutches and flee for help to a tiny village called Ponyville.
In Ponyville, Minty the earth pony is living in shame after her accident at the Winter Wishes Festival a few months ago. The plight of the runaway unicorn princess gives her a chance to redeem herself, but can Minty, a pony so clumsy that she seems to destroy everything she touches, save all ponykind from Sombra's menace? Only two things are certain: Ponyville's way of life will be changed forever, and she'll never make this work without a little help.
After all... what are friends for?
Those familiar with the source material -- which is hardly a prerequisite -- will notice that some events have been moved around in time, replaced, or otherwise modified. In particular, the name 'Christmas' has been excised in favor of the winter holiday from Twinkle Wish Adventure, since ponies celebrating Christmas has never once been a thing that made sense. This story is about the characters more than about the exact events (and order of events) as depicted in the animated specials.
As for the citizens of Ponyville, only the ones who showed up in the 2003-2007 (pre-"Core 7") animated specials are counted here. Toola Roola or Princess Peppermint, to pick two random examples from later releases or the massive toyline, do not count. Gem Blossom and Valenshy are also excluded from Ponyville despite their animated appearances, on account of being "jewel ponies."