I'm staying at my wife's parents' house for a week. I haven't seen my sister-in-law Rio in a while, but she always looks defenseless at home, and I don't know where to look. My relationship with Rio changed drastically the day she went out drinking with her friends. I decided to let Rio rest in a business hotel after getting drunk, but when I saw Rio's voluptuous figure, I couldn't control my reason... From then on, Rio and I hid from my wife and indulged in passionate creampie sex like lovers in love...