Hikaru, a daughter-in-law who is being pressured by her mother-in-law to give birth to her grandchild, is ordered not to have sex until a hot spring trip in a month in order to conceive. However, on the day of the trip, her husband refuses to have sex with her. 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, the father-in-law witnesses Hikaru's seductive bathing figure and is unable to suppress his desire...