Naoko, the daughter-in-law pressured by her mother-in-law to have a grandchild soon, finds out that the family will be going on a hot spring trip. However, for the sake of having a child, she is ordered to abstain from sex for a month leading up to the trip. On the day of the trip, Naoko is shockingly rejected by her husband when she tries to have sex. Meanwhile, her father-in-law also attempts to have sex with his wife but is similarly rejected. The two, unable to release their sexual tension, head to the hot spring to calm down. Then, the father-in-law accidentally catches a glimpse of Naoko bathing…
