Tsumugi is under constant pressure from her mother-in-law to produce a grandchild. When the family plans a hot-spring trip, she is ordered to abstain for a month beforehand to improve their chances of conception. Yet on the day of the trip, her husband refuses to have sex with her. Her father-in-law is similarly rejected by his wife. Both left painfully aroused, Tsumugi and her father-in-law head to the hot spring to cool down. When he accidentally sees her bathing, he can no longer restrain himself, beginning a secret encounter filled with repeated creampies and the fear that he may impregnate her.