A twenty-six-year-old drummer named Shibakusa Tooru is on the verge of a major label debut when his bandmates suddenly fire him. Devastated and spiraling into self-destruction, he learns that his former classmate and idol, the singer-songwriter Narahara Shigure, has died by suicide. Having lost his only emotional anchor, Tooru jumps from his balcony in despair. Instead of dying, he wakes up in his childhood bedroom, somehow transported ten years into the past to the very beginning of his high school years.

Determined to rewrite the worst possible future, Tooru resolves to prevent both his own ruin and the tragic fate that awaits Shigure. Using the knowledge and musical maturity he gained as an adult musician, he approaches Shigure—now a quiet and isolated high school girl—and proposes they form a band together. He also recruits Risa Kataoka, a delinquent with a reputation around school, to complete their three-piece lineup. Risa initially carries her own baggage from the original timeline, where she was expelled, but Tooru’s insider knowledge of the past helps him steer her away from that path.

The story follows the trio as they navigate high school life and the grueling world of amateur bands. Tooru’s experience as a near-professional musician gives him an edge, but he is far from invincible; he struggles with his own past mistakes and the weight of trying to change events he barely understood the first time. A major early narrative arc involves their attempt to enter a local festival called Mikansei Festival, where they must face off against Tooru’s former bandmates from the original timeline, creating a direct clash between the future Tooru is trying to escape and the new one he is building. Through rehearsals, personal conflicts, and the pressure of live performances, the manga explores themes of second chances, the bonds formed through music, and the painful but rewarding process of growing up all over again.