His wife Rio is under pressure to give birth to her grandchild. - One day, at my father-in-law's suggestion, the whole family decided to go on a hot spring trip. - However, in order to have a baby, her mother-in-law orders her to abstain for a month before the trip. - On the day of the trip, Rio's husband refuses to have sex with her. - Meanwhile, his father-in-law also tries to hold his wife, but is refused. - The two, overcome with sexual desire, headed to a hot spring to soothe their aching bodies. - And her father-in-law happened to witness Rio taking a bath...