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 a hot spring to calm their bodies, but when Mahiro's father-in-law happens to see her bathing, he can't control his desire...