In this story, Seto Inland Sea is not a place name, but the name of two second-year boys in a boys' high school in Osaka. Seto Kokichi (played by Masaki Suda) is thin and tall. He was a member of the football club, but he quit the club because of a bad relationship with his senior. Utsumi So (played by Sosuke Ikematsu) is gentle and taciturn, but he is not a nerd who only knows how to study. Somehow, these two "home clubs" who seem to have no intersection became friends. Every afternoon after school, they make an appointment to sit by the river. During this time before Utsumi goes to cram school, the two chat about everything. Their topics are all-encompassing, but boring and empty. When the fairy-like girl Kashimura Ichiki (played by Ayami Nakajo) appears, she inadvertently stirs up waves in the heart of the dull big boy... This film is adapted from the manga of the same name by Motowa Tsuneya.