During the summer of my third year of university, my mother, worried about me being consumed with studying, asked me to take a vacation, so I decided to stay at my uncle's house in the countryside for a week. In the countryside, I was greeted by my domineering uncle and the chaste Rinko, and felt nostalgic for the two of them who had not changed at all. A few days later, I found the supposedly chaste Rinko having a secret rendezvous with a man at the front door. There, Rinko was controlling the man in an overwhelming master-servant relationship. I was stunned by her completely different appearance from usual, and that night she invited me to tell her a secret...