When my mother-in-law asks when she will finally see a grandchild, I am shaken. What should have been a pleasant family hot-spring trip becomes a planned opportunity for my wife and me to conceive. I endure a month without sex as instructed, only for my wife to refuse on the day of the trip. Frustrated and restless, I wander through the inn and accidentally see my mother-in-law bathing. Desire overwhelms me, leading to repeated creampies during the overnight trip and, as the title reveals, her pregnancy.