Mahiro, a daughter-in-law, is pressured by her mother-in-law about when she will have a grandchild. One day, the 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, Mahiro 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, but when Mahiro's father-in-law happens to see her bathing, he can't control his desire...