Mio, a daughter-in-law, is under pressure to give birth to a grandchild. One day, she wins a trip to a hot spring in a lottery at a shopping district and the whole family decides to go on the trip. However, this trip was planned by her mother-in-law to have a baby. On the day of the trip, she asks her husband to have sex as ordered by her mother-in-law, but he refuses. Meanwhile, her father-in-law also tries to embrace his wife, but he refuses. The two, with their sexual desires at their disposal, head to the hot spring to calm their bodies. Then, by chance, her father-in-law sees Mio taking a bath...