Yui lives with her daughter, husband and daughter-in-law. The family lives a peaceful life, but one day, Yui's underwear is stolen! Yui is creeped out, "Who would steal an old woman's underwear..." but the culprit is her daughter's son-in-law! The son-in-law, who has been fascinated by Yui's big breasts for a long time, explodes with desire and finally attacks Yui! Frustrated, Yui is unable to refuse and ends up being played with by her son-in-law like a toy...