Yuka and her husband are trying to have a baby because her father-in-law has started to suffer from cataracts. However, due to the pressure, Yuka's husband's penis is useless and Yuka becomes frustrated. One day, while taking care of her father-in-law, Yuka discovers that his penis is erect and she indulges in masturbation. Gradually, Yuka's desire grows, and she even starts taking care of her father-in-law's private parts...