Starlight Glimmer's time travel spell affected not only Equestria, but also the land on the other side of the mirror. In this universe, Sunset Shimmer never met Twilight Sparkle, and her reign over CHS has not weakened one bit. But, unbeknownst to her, she isn't the only Equestrian in this human world, as the three Sirens known as the Dazzlings have sensed the magic coming from the school.

Now, it's Sunset Shimmer vs Adagio Dazzle. Who will be the one to rule the school?