I am Hatano Kyouichi, 34 years old. I have been married to my wife, Yui, who is the same age as me, for seven years, but actually, the sex with my wife is... lacking. One day, burdened with such a hazy烦恼, I witnessed the good-looking young man Hashimoto-kun from the floor above coming out of our house. After a few days passed... suddenly, my wife became erotic.