Thanks to Twilight Sparkle and her friends, Equestria has known its longest period of peace! Except for the reoccurring existential threats. And if you ignore that thousand years when the Elements of Harmony weren't needed.
Well, that time is over. A new villain has come to tame the mythical land of magical horses. Or, well, he's there at least. Equestria has a way of taming itself.