Nobuo lives with his wife, along with his divorced father-in-law and his soon-to-be mother-in-law Sayuri. One day, his wife is going on a business trip abroad for a month. After Shiori, the daughter of her prospective mother-in-law from her ex-husband, enters college, she lives with Ola in the countryside. However, Shiori falls in love with her Nobuo at first sight. However, Nobuo had an inappropriate relationship with his prospective mother-in-law without his family's knowledge. Shiori, her daughter, who accidentally witnessed the two of them, uses it as an excuse to seduce Nobuo...