My respected brother and my sister-in-law Yuu, whom I adore like a real sister. I ended up living with this happy couple for a short time, and I was enjoying my life. However, my sister-in-law was acting a little strange. There were suspicious visitors, and she seemed to be hiding something... There's no way my sister-in-law would cheat on me. In order to protect the peace of this house, I decided to take action. I believe in my sister-in-law... The first in a new drama series about sister-in-law being cuckolded!