His wife, Lisa, is about to give birth and has returned to her parents' home. Kenichi feels inconvenienced, but he is enjoying life alone and remembers his days as a single man. One day, Lisa's sister, Yumiko, comes to visit him out of concern. "I'll take care of the household, so it's okay." He has a reason for refusing Yumiko. He is attracted to her as a member of the opposite sex and does not have the confidence to control his instincts. "Aren't you pent up?" Yumiko asks, whether she knows Kenichi's feelings or not, and she says something that could be interpreted as a temptation...