Risky House-sitting with My Stepbrother

While my parents and my stepbrother and his wife are on vacation, I have to take care of my stepbrother Iku-chan. One day, Iku-chan, who is full of energy and mischievousness, finds one of my treasured erotic books. She innocently seduces me by imitating the book, and my rationality is finally shattered.... Full of eroticism in the name of curiosity, without any sexual awareness!