Many couples in Japan today are troubled by infertility. Hayato and his wife Sakura are one of those couples who are suffering from such a problem. They have been trying hard every day for the past few months to have a baby, but they have not seen any results. "Hey, why don't you abstain from sex for a month and save up some thick sperm?" Sakura suggests, as a last resort, and Hayato decides to abstain for the sake of his child. However, he had no idea that his mother-in-law was eagerly setting her sights on his cock, which was about to explode at any moment...