First-year high school students Kana, Reimi, and Hibiki are apprentices at the Karasuma Phoniatric Clinic, where the power of healing through song is combined with conventional medicine. One day when the girls' teacher is out, one of the clinic's patients takes a sudden turn for the worse. Is there nothing these apprentices can do to help?
That's why it feels like the sky 
deep in our hearts is blue and clear
لذا كأنّ السماء في أعماق قلوبنا
زرقاءٌ وصحوة
Deshalb fühlt sich mein
innerer Himmel ach so blau an …
Ed è per questo che il cielo nel profondo
del nostro cuore sembra limpido e blu
É por isso que o céu
no fundo do coração é todo azul
Потому и кажется, что небеса
наших сердец синие и ясные.