My sister Nao, who lived an otaku life in the countryside, came to Tokyo from her hometown as soon as she graduated from college. I don't have a job or a room, so I decided to stay at my sister's house until I found it. However, the night life of her sister and her husband is not odd, and her sister Nao is shocked. A fierce piston that seems to break, a pant voice like a scream, a peek at the appearance of my sister who bends over the body and reaches the climax many times, and involuntarily wets the crotch. And he can't stop his overflowing desires and takes bold action ...