Kanna is under constant pressure from her mother-in-law to produce a grandchild and is ordered to abstain from sex until a hot-spring trip a month later. When the day finally arrives, her husband refuses to try for a baby. Meanwhile, his father is also rejected by his wife. Both sexually frustrated, Kanna and her father-in-law head to the baths to cool down. When he accidentally sees her sensual body in the water, he can no longer contain his desire.