Ponyville is a place where the impossible happens. This ranges from having a dragon as a neighbor to having an infestation of bugs that can eat things 100x their size. Though Ponyville is special, it's still an ordinary small town, and in small towns rumors travel fast. That's why when somepony figures out a way to explain everything bad that's happened, a whole town can turn on one pony. Even if that pony has helped them countless times. Even if that pony is royalty. Even if that pony is Twilight Sparkle.
Only one pony, the forever loyal Rainbow Dash, believes her when she says that she's innocent. The two of them will have to work together if they want to clear Twilight's name and prove that she's not the cause of everything that goes wrong in Equestria. They will have to work hard, though, if they want to win the fight against everypony in Ponyville, including even Twilight's closest friends.