"Big brother," a familiar voice said. - The owner of the voice is Natsumi, a childhood friend who lives nearby. - Natsumi, who was three years older than me, was a friendly girl who was always smiling by my side. - I'm not being conceited, but she liked me. - Natsumi, whom he met again when he returned home for the first time in five years, was much more mature and sexy than the Natsumi he remembered. - It was the first time I became conscious of Natsumi as a member of the opposite sex. - But Natsumi already had a boyfriend. - So I...