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.

Masato, adoptive son of the Kuwabara household, has always been surrounded by prosperity... Until one day the head of the family brings home a child named Kenta. Drowning as he is in the despair of having outlived his purpose, Masato still doesn't fail to notice the undue attention the master has started paying Kenta...