Hitomi is a sheltered girl who has been going to her regular clinic, Kobato Clinic, for any injuries or illnesses since she was a child. The annual health check is a family tradition, and has always been performed by the clinic's director, Kobato Taro. Hitomi has begun to feel embarrassed about her physical growth and about showing her naked body to the opposite sex. Hitomi has been told that she will be having a vaginal examination starting this year... She feels anxious, but the day of her annual health check arrives.