Akiho, who became my father's wife and joined our household, is only three years older than me. It seems they met through my father's university connection, as she was his former student. Since my father married a younger woman, his nights have become constantly busy, and I often hear Akiho's moans coming from their bedroom. Drawn to those sounds, I began secretly watching my father and Akiho's intimate moments, which gradually intensified my attraction to her sensual charm, bringing a new kind of excitement into my daily life.