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!

Let me hear that harmony again!
!أسمعوني ذاك التناغم من جديد
Wo ist der Akkord von eben?
Also dann! Drei, vier …!
Hagan lo de antes.
Haced lo de antes.
Une petite harmonie de plus.
L'armonia di poco fa!
A harmonia de antes!
Кричите в унисон снова!