As spring arrives and the weather gradually warms, I had planned a dinner together with my wife and her older sister, Tomoka, who always exudes a warm and gentle presence. Tomoka carries herself with a quiet charm and mature allure that has always deeply attracted me. That evening, just as the three of us were about to toast, a massive blackout suddenly struck. My wife was called away to the hospital, leaving me alone with Tomoka until morning. Frightened by the darkness, Tomoka couldn't bear to stay apart from me. Unable to maintain self-control, an entirely new emotion began to stir between us—something that had never existed before.