All characters are portrayed by adults. Nao and I are not blood relatives; she became my older stepsister when my father remarried during my school days. After our parents died in an accident, the much older Nao raised me in their place. Life together could be lonely, but I was also happy because I had fallen in love with her. One day, I found my best friend Yuzuru whispering with Nao. They brushed off my jealous questions, but soon afterward she began coming home late again and again.