After the Dazzlings were defeated at the Battle of the Bands, Princess Twilight went back to Equestria, leaving Sunset Shimmer as a new singer for the Rainbooms. It's been a long time since she did anything musical, so she's getting back into practice. However, they couldn't have won without the help of Vinyl Scratch. Yet, she has no clue why she helped them. For that matter, she doesn't know ANYTHING about her! Will a chance meeting in the school's music room help Sunset learn who Vinyl really is?