Hikaru, a wife who is under pressure from her mother-in-law to give birth to a grandchild, is ordered not to have sex until she goes on a hot spring trip in a month's time in order to have a baby. However, on the day of the trip, her husband refuses to have sex with her. Meanwhile, his father-in-law also tries to hold his wife, but he is also refused. The two, overcome with sexual desire, headed to a hot spring to soothe their aching bodies. And when her father-in-law happened to witness Hikaru's sexy bathing appearance, he could not suppress his desire...