Hiroko works as an assistant at a dental clinic while attending school to get her dental hygienist certification. At the clinic, the director's son, Takashi, does no work and constantly interferes. During a lunch break on a particularly busy day, Takashi comes to the examination room for a teeth cleaning. Since the doctor is busy preparing for an academic conference, Hiroko reluctantly agrees to do it as practice... From then on, using cleaning as an excuse, Takashi subjects Hiroko to all sorts of sexual abuse.
