Nina, the daughter-in-law, is pressured about her grandson's birth. One day, at her father-in-law's suggestion, the family decides to go on a hot spring trip together. However, for the sake of having a child, she is ordered by her mother-in-law to abstain from sex for one month leading up to the trip. On the day of the trip, Nina is surprisingly rejected by her husband for sex. Meanwhile, her father-in-law also tries to have sex with his wife but is rejected. The two, overwhelmed with sexual desire, head to the hot spring to calm their bodies. Then, the father-in-law happens to catch a glimpse of Nina's bathing figure…
