JUL-992 My beautiful sister, who I would never mess with, and I are stepchildren who are not related by blood... - On a summer day, the two lose the bond of being siblings and indulge in a forbidden affair. - Ayame Tsuzaki

At the beginning of summer when we could hear the sound of cicadas, my older sister Ayame and I were returning home to celebrate the 17th anniversary of our mother's death. - The reason I went back to my parents' house every year was because of my older sister Ayame. - She was my kind and admired older sister who took care of me in place of my mother who passed away at an early age. - Although we are both married, I still have special feelings for my sister, more than family. - Then, on the night after the memorial service, my father, who had a mysterious look on his face, called me and confessed to me that we were not really siblings.