My wife, who was about to give birth, went home. Keita, who was enjoying one person for the first time in a long time, remembered his bachelorhood and dignifiedly caught erotic images in the living room. Then ... "It's hard work until late ♪" When I turned to the sudden voice, it was my wife's sister Miyuki who was there. Keita hides her crotch in a hurry. However, Miyuki throws a shocking word at Keita. "You were alone a while ago ... Then let's do it together next time." It's only one week until the expected date of delivery. A long and short living together with my sister who is too erotic has begun.