After my mother died early, my father, who raised me alone, and my childhood friend, Sumire, were the ones who supported me through my depression. Sumire and I had always been close childhood friends, but we had been dating for about a year and we had been thinking about getting married. Then, to tell my father about our marriage, I arranged a meeting with Sumire and him to talk, but I didn't notice that my father was acting strangely at that time...