Reno is constantly pressured by her mother-in-law to produce a grandchild. Before a family hot-spring trip, she is ordered to abstain for a month so she can try for a baby there, only for her husband to reject sex on the day they arrive. Her father-in-law is similarly turned down by his wife. Both burning with pent-up desire, Reno and her father-in-law head to the baths to cool off. When he accidentally sees her bathing, he loses control, beginning a trip of repeated creampies that leaves her pregnant with his child.