Tsumugi, a daughter-in-law, is pressured by her mother-in-law to give birth to a grandchild. One day, the whole family decides to 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, Tsumugi is refused sex by her husband. Meanwhile, her father-in-law tries to embrace his wife, but is also refused. The two, with their sexual desires at their disposal, head to the hot spring to calm their bodies. Then, by chance, Tsumugi's father-in-law witnesses her bathing and can't control his desire...