26-year-old office worker Erina has a voluptuous E-cup bust that looks both elegant and sexy under her clothes. Working in central Tokyo, she speaks in a refined, gentle tone: "I'm never satisfied with my boyfriend in bed, so I can't stop masturbating..." But in truth, she's deeply aroused by adult videos and harbors a surprisingly lustful nature. To relieve daily stress, she meets with an animalistic male performer, unleashing her hidden pleasures. As she climaxes repeatedly, she keeps whispering, "I'm sorry!" Throughout the experience, Erina evolves into an honest woman who embraces her desires and learns to take control of her own pleasure.