Mio, the wife who is being pressured to have her grandchild born. One day, the family decides to go on a hot spring trip that she won in a raffle at the shopping street. However, this trip was a baby-making trip planned by her mother-in-law. On the day of the trip, she invites her husband to sex as instructed by her mother-in-law, but he refuses. On the other hand, her father-in-law also tries to hold his wife, but she refuses. The two, unable to contain their sexual desire, went to the hot spring to calm their restless bodies. And then, by chance, her father-in-law witnesses Mio's bathing figure…
