Time has passed since the events of Equestria Girls.

And Sunset Shimmer's demon was locked away.

Or was it?

One night when Sunset thinks about going back, The demon is released once more, Only this time it separates itself from Sunset Shimmer's human body and flies to Equestria solo.

Weakened by this occurence, Sunset enlists the aid of the Spirits Of Harmony to destroy the demonspawn once more and save both worlds from utter destruction