ROYD-267 A brother and sister gradually fall into temptation, drawn in by the allure of his slender, busty older stepsister.

My father remarried, and my sister and I gained an older stepsister. She was cheerful and beautiful, but it was hard not to notice her figure. Then one day, I was tempted by my stepsister and lost control, leading to a secret relationship. If our family ever found out, it would be a disaster… But even my serious younger sister was taught about pleasure by our stepsister, and before long, the three of us ended up hiding our relationship from our parents and becoming intimate together.