Tachibana Shiho is a genius neurosurgeon. However, after being in an accident, she started having visual hallucination while performing surgeries. Due to this symptom, Shiho decides to quit her profession. Then, Kitabatake Masayuki, her former professor who is currently the Director of Toko University Hospital, persuades her to join the Department of Analysis and Diagnosis, also known as "Lady da Vinci," at his university hospital. Lady da Vinci is a team of seven female diagnosticians who are all extremely talented in their expertise yet each seems to have a very distinct personality all their own.