The story is set in a world where three schools of medicine are pervasive: Western medicine, Eastern medicine, and "vocal medicine." The healing of illness and injuries via songs is a special technique that not only improves the mental health of patients, but also the mental health of doctors. Such "Healers" strive to sing when called upon to respond to the health and anxiety of patients and doctors alike. The anime depicts the healer girls in training at the Karasuma Vocal Medical Institute.
(Source: ANN)