One night in 1986, the twelve year old Lauren Faust wakes up finding a talking pony under her bed. She follows the pegasus though a tunnel into a place called Equestria.
Lost her magic. Kicked out by Aria and Adagio. Going it alone. Not a good week for Sonata Dusk. Lucky for her, a certain someone decides to give her a second chance.
Think of a beautiful, extremely sophisticated, humanized Rarity. Now think of a hideous version of her. Yep. You're looking at Rarity before her transformation.