Eri is a melancholic yet sensual office lady working in accounting. She hasn't had a boyfriend in over a year, and her daily life consists of nothing but commuting between work and home. Despite being in the prime of her womanhood, her body aches with pent-up desire. She masturbates four or five times a week, yet still finds herself suddenly overwhelmed by intense arousal during work hours or on her train commute, driven by urges she can no longer suppress. Long curious about adult filming, she decides to sign up and submit her body to the touch of a stranger's fingers. Her reasons for taking this bold step, and the emotions stirring within her, are about to unfold.