"My little ponies, it is with great relief that I can finally tell you: The Crystal Wars are over. With the end of hostilities, my daughter --your hero-- Sunset Shimmer, is coming home."

After twelve long years, Sunset Shimmer is coming home. To Canterlot. Through twelve years of hard, bloody campaigning, Sunset had finally ground the Crystal Empire, and by extension the tyrant, Sombra to dust under her hooves. And she's coming back to Canterlot, the place of her birth.

As for Princess Celestia, The Celestial Monarch. She has waited for her daughter to come back so that she may impart one final lesson. But Sunset Shimmer has a lesson of her own:

War. War never changes. But ponies do.