Maki Koizumi is a widow; her husband sadly passed away from a serious illness, which has left her heartbroken and with no intention of remarrying. Although she is not young anymore, Koizumi looks quite youthful with smooth, rosy-white skin. Due to not having contact with men for a long time, emotional deprivation is unavoidable. For this reason, whenever her young cousins come to visit, she always flirts and teaches them about intimacy, both to satisfy her own needs and to help these young men mature in their romantic lives.