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!

Because, you see, this world...
...فهذا العالم
Immerhin … besteht
unsere Welt aus Noten!
Porque este mundo…
Porque este mundo…
Parce que notre monde
Perché questo mondo
Afinal, o mundo é feito de notas musicais!
Понимаешь ли...