At the beginning of summer, when the sound of cicadas was heard, my sister Ayame and I were returning to our parents' house for my mother's 17th bereavement. The reason why I went back to my parents' house every year was because of the presence of my sister, Ayame. - She is a gentle and longing sister who took care of me in place of my mother, who died early. Although they are both married, I still have a special feeling for my sister that is more than family. - And on the night when the ceremony was over, my father with a mysterious face called me and confided in me that we were not real siblings.