Former Canterlot High School bully and student of Princess Celestia, Sunset Shimmer, who has reformed after being defeated by the magic of Twilight Sparkle's crown, is ostracized by most of the school despite her efforts to atone. Her only friends are the counterparts of Rainbow Dash, Applejack, Pinkie Pie, Fluttershy and Rarity, who have formed a rock band called "the Rainbooms" to participate in the school's upcoming musical showcase. The five girls discover that the magic left over from Twilight's crown has given them the ability to grow pony-like ears, tails, and wings when they play their instruments.