Sora no Woto Description:
The story is set long in the future where the world has seen many wars and has settled into a quiet decline. The story begins as Kanata Kumika, a 15-year-old girl who enlists with the army, was assigned to a unit of five girls as they defend a fortress. It also seems that music would play an important part of the series, since the series has some pretty heavy emphasis on the girls playing music across lands from their fortress.
Sora no Woto Episodes: