JUQ-128 My beloved stepsister, who raised me single-handedly, was stolen by her shitty friend... Mukai Ai

Aoi and I are not real siblings. During our student days, my father remarried, and Aoi was the child from that marriage. One year later, after both of our parents passed away, Aoi became my guardian. As we lived together, I began to develop special romantic feelings for Aoi, the only family I had left. Just as I vowed to make Aoi happy in the future, my bad friend Shinji started approaching our family. 'Your sister is quite sexy and beautiful, huh.' He said this and started frequenting our house...