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!

So we're gonna keep filling it with color
لذا سنواصل ملأه بالألوان
Debemos colorearla.
Debemos colorearla.
И мы наполним её всеми цветами.