One day, my father remarried. His stepdaughter, Chiharu, came to our house as my step-sister. One day, my parents went out. I was left alone with Chiharu. The two of us were more aware of each other than usual. And without a word of conversation, we silently desired each other's bodies. From that day on, my relationship with my sister began, where we would silently desire each other's bodies whenever our eyes met...