Koyoi Oto Furu Sora no Shita

Miyabi has lost her voice from losing her happy family, and she is adopted by Naozumi who runs a piano school. There, she meets Yue. Yue has loved Miyabi's piano-playing since he was small; he stops playing piano, and looks at Miyabi who closes her heart to the world. Thus, he becomes desperate trying to bring her back to the world of sound, but...

(Source: Midnight Scans)