Tenshi, Ei-chan, and Shiratori all attend Kawagoe Academy. One day, they get pulled into the orbit of former conductor Haruo. He drags them into his newly founded boys choir where they suddenly find themselves performing a song in front of an audience!

That's right! The world 
is made of musical notes!
!صحيح! العالم يتشكّل من الألحان الموسيقيّة
Wie ich schon sagte:
Unsere Welt besteht aus Noten!
Exacto. El mundo está lleno
de notas musicales.
Exacto. El mundo está lleno
de notas musicales.
Eh oui,
c’est même la musique qui l’a créé !
Già.
Isso mesmo! O mundo é
feito de notas musicais!
Да-да! Весь мир состоит из нот!