One night and two days of 1 night and left alone by my wife's sister who suddenly came over

Her wife, Lisa, had returned to her parents' house with her child coming up soon. Although Kenichi felt inconvenient, he recalls his days as a single person, enjoying life alone. One day, Lisa's sister Yumiko (Kanade Jiyu) visited us in worry. "It's fine as I can manage my own house," there was a reason why Yumiko refused. Kenichi has long been attracted to Yumiko as the opposite sex, and in a situation where she is alone with Lisa, she hasn't had the confidence to control her instincts. "Isn't it piling up?" Yumiko, who knew Kenichi's feelings or not, said something that could be interpreted as a seductive thing...