Tamai Shiina, a cheerful girl, met a weird star-shaped creature during her visit to the island where her grandparents lived in the last summer of elementary school. "Because the star is round," Shiina gave a name: "Hohsimaru" the round star to that creature, which could fly to the sky. Starting with that, Shiina met other boys and girls who also befriended with Hoshimaru's friends. What exactly was the real shape of Hoshimaru's body? The world scale magnificent story begins.