Koji harbored a secret admiration for his beautiful, kind, and stunningly attractive aunt, Yoshika. He had been living with her while attending school, but constantly struggled with awkwardness and unbearable tension. Meanwhile, Yoshika's relationship with her husband had grown distant since Koji moved in. Left unfulfilled night after night, she began indulging in masturbation in the bathroom to satisfy her desires. One night, Koji accidentally witnessed his aunt's lewd act. From that moment on, their relationship took a drastic turn.