After getting married, the husband has not had sex for a long time due to a slump in their relationship, so he secretly calls a "real sex delivery health" service he has heard about. However, the person who visits the husband at the hotel is his wife's younger sister. He tries to refuse, but his wife's younger sister, who has been serving him for work, stimulates his body and makes his crotch swell. The more he thinks that it is wrong, the more he is engulfed in an unstoppable whirlpool of arousal.