With less than two months until the birth, cheerful mother-in-law Ayano comes to town to support her emotionally unstable pregnant daughter. The home brightens, but after the husband lets his guard down, his wife forbids him even to masturbate. He holds out for a day, three days, then a week until he finally snaps. While Ayano is bathing, he steals her underwear and masturbates while sniffing it—only for her to catch him in the act, setting the stage for repeated forbidden breeding sex.