Twilight Sparkle, apprentice of Queen Celestia, must find and bind six ponies to the Elements of Harmony, to defeat the monsters that hold the Queen and Princess hostage. Also, Fluttershy is a vampire. Not a problem.
In the far future, after the Changeling War, seven very special ponies weild the Elements of Harmony to defeat Sombra and rescue the only living alicorn in Equestria left: Princess Flurry Heart.