One day after school, Masaru helps his stepmother Saori retrieve something from her sister Miyuki's house. But when Masaru arrives, he catches his stepaunt in the act of pleasuring herself—while calling out his name! Noticing Masaru, Miyuki invites him in and has her way with the inexperienced young man. Soon, the worried Saori checks up on why her sister and stepson are not picking up...