Shouta Handa, a disillusioned 25-year-old without a job, reunites with his former classmates at a gathering, only to be confronted by their remarkable transformations into successful and stunning individuals. Taunted for his lackluster life, Shouta stumbles into a time-traveling mishap after falling into a school pool, transporting him a decade back in time. Now inhabiting his younger self's body, he must navigate the challenges of interacting with his female classmates, who now appear alluring and close in their teenage forms. How will Shouta handle this bizarre twist of fate and newfound proximity to the girls he once knew?