Shion Hagino is a 29-year-old beauty consultant. Although she has never had a boyfriend, Shion leads a happy and fulfilling life. However, one day, Shion participates in a blind date party and it triggers a flashback where she was rejected by her first love back in high school, who told her, "If you're going to confess, you should at least do something about your appearance". As if drawn back by her past trauma, Shion somehow goes back in time and becomes a 17-year-old high school student again. Using the makeup techniques she has honed, Shion decides to move towards a different timeline as compared to what happened 12 years ago.
Ritsuka Uenoyama is bored with it all—with school, with his basketball club, and even with his one true passion: playing guitar. That is, until the day he finds his favorite hidden napping spot occupied by a strange boy cradling a broken-stringed guitar. At first, Uenoyama is nonplussed by Mafuyu Satō and his slightly odd behavior, but when, on a whim, he asks Mafuyu to sing, the power of that song pierces him to the core.