When her crown is stolen from the Crystal Empire, Twilight Sparkle pursues the thief, Sunset Shimmer, into an alternate world where she finds herself turned into... a teenage girl! To regain her crown, Twilight must defeat Sunset Shimmer and be crowned Princess of the Fall Formal at Canterlot High. Luckily, she'll have the assistance of Spike and five teenage girls who remind her of a certain group of ponies back home.