Sweetie Derelle, the alternate reality Sweetie Belle, has arrived in Equestria to save everyone. That includes driving a bus at high speed through Canterlot to make sure it doesn't explode. Also into Canterlot Castle. Specifically Celestia's Bedroom.
Years ago, Sweetie Belle's parents sent her to live with Rarity for a better education than their little town could give her. Now with a new school and new teacher, they have come to take her back, forcing her to leave Ponyville and all her friends.
Five years of cheap thrills in the big city has left Sweetie Belle in bad debt with dangerous ponies. Forced to pay up, she returns to Ponyville to seek money from an estranged sister she loathes with a passion.
Sweetie Belle has a long record of little "accidents." It seems like everything she does just ends in disaster. After a fight with Rarity, Sweetie is left to wonder if she really is cursed. Is there anypony to convince her otherwise?