After losing her parents in a heartbreaking accident 13 years ago, Aoi Aioi has relied on her older sister, Akane, as her sole caregiver. To show her appreciation, Aoi plans to attend a music school in Tokyo after her high school graduation, relieving Akane of her responsibilities. A key source of inspiration for Aoi is Akane's ex-boyfriend, Shinnosuke "Shinno" Kanamuro, who left their hometown to pursue his musical dreams after the family tragedy. Unexpectedly, version 18-year-old Shinno arrives at the guest house where Aoi practices her bass, bringing uncertainty and confusion to the family dynamic. Later on, the 31-year-old Shinno appears in town, but he is different from the Shinno they once knew. The family is left wondering how two versions of the same person could exist and what the younger version is doing here. In Sora no Aosa wo Shiru Hito yo, Aoi, Akane, and both versions of Shinno navigate their complex emotions and make difficult choices that will impact their futures.