Sombra invaded Equestria and won. Celestia and Luna are no more and the Main 6 has been defeated. A mute colt survivor lives with with a powerful gem that Sombra wants at any and all costs.

Twilight and the rest of her friends get summoned to a world where music is magic. The king of the world or the "Master Conductor" saw that they restored harmony to their world time after time and he hopes they can do the same to his.

Doctor Whooves being the local and only Timelord of Equestria he deals with threats so that Equestria can remain the happy loving place he wants it to be.