Every summer break, Kazu-kun spends a week with his beloved uncle Tetsunosuke, who lives in a mountainside village and works as a textile maker. Yuubae ni Niji is the story of their colorful days.

Shintaro Kuze, a fledgling writer, ends up staying at his former teacher's house. There, he is also taken care of by a calligrapher named Shogo Kuzuki, who the shy Kuse finds quite uncomfortable. One day...