Hiroko works as an assistant at a dental clinic while attending school to become a certified dental hygienist. At the clinic where she works, the clinic director's son, Takashi, does no work and only gives orders. One day during lunch break on a particularly busy day of appointments, Takashi comes to the examination room for a teeth cleaning, but the doctor is too busy preparing for a conference, so Hiroko reluctantly takes on the task as practice... From that point on, Takashi uses teeth cleanings as an excuse to subject Hiroko to all manner of molestation.
