The second son of a rural man of property, Kyuu, has been best friends with Toshio since childhood. As Toshio grows up, he secretly falls in love with Kyuu. One day, Kyuu's older brother Sumi, who had run away from home, coincidentally comes in contact with Toshio. Then, Sumi invites him to deepen their relationship! This is the "Son of the Mimura Family" series, which depicts adolescence wavering in the rift between friendship and love.