On a summer day with the loud sounds of cicadas, I returned to my parents' house for the first time in a long time for the 17th anniversary of my mother's death. The reason I always returned every year was largely due to my older sister, Riho. She was the sister I looked up to and always looked after me in place of my mother, who passed away early. Now that we're adults, my sister and I are both married, but I still have special feelings for her that are different from those I have for siblings. Then, at night after the memorial service, my father called me to talk to me, and it was there that he confessed to me that my older sister, Riho, and I weren't actually siblings...