The serious-looking woman turns out to be the filthiest. I am alone in the quiet office with Yamagishi from general affairs, a coworker I thought I would never get along with, until a small incident unexpectedly brings us together. We secretly drink after work, her expression suddenly changes, and she kisses me before we have raw sex right there in the office. I never imagined Yamagishi was this horny. For one secret week, before the other employees arrive, we indulge her enormous sex drive with repeated office sex while keeping the affair completely hidden from my wife.