Shiraki Yuko's second appearance as a Ruby exclusive features the "Mother-Son Copulation" theme. After a divorce, her two sons are separated, each raised by one parent. The older brother grows into a responsible adult, while the younger brother, unable to get along with their father, leaves home. When their father suddenly passes away, the family reunites for the first time in years at the funeral. Wing and Yuko, meeting after several years apart, decide to take a hot spring trip together to reconnect. Wing, starved for maternal affection, gradually succumbs to twisted desires. Yuko, understanding his emotions, chooses to accept them. Depicting an intense, forbidden incestuous relationship unfolding during a hot spring journey meant to make up for lost time, this work explores the complex bond between mother and son, blending love and inner conflict.