Sunset Shimmer, one of the Celestia's most powerful student, that lived in the human world, went back to the pony world and now have to face the consequences and save the day, now being an Alicorn.
Moonlight Glare was a gifted Unicorn that lived in a small city called St. Hooves, but he accidently turns into an Alicorn, and now has to struggle to undo this.