My wife's mother is beautiful and attractive even as she ages. Apparently she had been asked to work as an underwear model, and since her breasts seemed to be swell, she came to Tokyo and ended up staying at our house. Even though she thinks it's naughty, she secretly opens her mother-in-law's room late at night and finds her mother-in-law practicing posing in her underwear in front of her mirror. Seeing her fair-skinned and bewitching lingerie appearance in front of her, the male can no longer suppress his emotions.