After a family tragedy, high school student Aoi Aioi lives with her older sister, Akane, who has been her sole caregiver for 13 years. Aoi dreams of moving to Tokyo after graduation to pursue music, inspired by Akane's ex-boyfriend, Shinno, a former band member who vanished after their parents' death. One day, Aoi encounters a younger version of Shinno from 13 years ago, coinciding with the return of the current, transformed 31-year-old Shinno. As the two Shinno's coexist, mysteries unfold, leading Aoi, Akane, and both versions of Shinno on a journey of self-discovery and life-altering choices in Sora no Aosa wo Shiru Hito yo.