Yukari Ouchi (60) was asked to house-sit while her son and daughter-in-law went on a trip. Upon hearing that her grandson Masaki would be visiting, she canceled her own plans and stayed home. The time spent alone together brought innocent, heartwarming moments, and Yukari found herself smiling genuinely for the first time in a while. Meanwhile, Masaki, bored and idle, began developing feelings for his older grandmother. Having lost her husband years ago and long deprived of intimacy, Yukari slowly awakened to sexual desire again—and eventually gave in to passion with Masaki. Their grandmother-grandson bond transforms into something deeper, as their forbidden relationship grows stronger through physical intimacy.