Kokoro, a daughter-in-law, is under pressure to give birth to a grandchild. One day, her mother-in-law suggests that the whole family go on a trip to a hot spring. However, in order to conceive, her mother-in-law orders her to abstain from sex for one month until the trip. On the day of the trip, Kokoro is refused sex by her husband. Meanwhile, her father-in-law also tries to embrace his wife, but is refused. With their sexual desires at a loss, the two head to the hot spring to calm their bodies. Then, by chance, her father-in-law witnesses Kokoro bathing...