After losing his wife, Yuuzou, the father-in-law, ended up living with his son's family. While his son is at work, he is alone with his daughter-in-law, Yoshi. Yuuzou is drawn to Yoshi's kindness and her large, swaying breasts every time she cleans or practices yoga. Eventually, Yuuzou, who is about to break the taboo of "taking his son's wife," will overcome his desire for Yoshi's large breasts...
