Koi is feeling a bit nervous as she boards the Shinkansen. She's not particularly dissatisfied with her married life, but having sex once or twice a week isn't enough for her, and she has a man with whom she has a physical relationship only. This is surprising, considering her quiet impression. When she puts on the remote control vibrator, she seems to have a bit of a masochistic streak, as her body responds too well and she quickly becomes melting. She becomes addicted to sex with a man she's just met for the first time, both in body and Kokoro...