One day, my father remarried, and his new partner's daughter, Chiharu, moved in as my stepsister. A few days later, while our parents were out, Chiharu and I were left alone together. With heightened awareness of each other's presence, we began seeking physical contact more than conversation. From that day on, an unspoken rule formed between Chiharu and me: whenever our eyes met, we silently sought each other's bodies. Without hesitation or guilt, our days of communicating through intimacy had begun.