(輪舞曲Duo -夜明けのフォルテシモ- ぷにゅぷりff) is an adult-oriented Japanese visual novel released in 2014 by the doujin developer TinkleBell . Key Game Information
The story is set in a school setting and revolves around supernatural or "devilish" impulses:
The plot centers on a dark rumor of an "after-school devil" and a infectious curse affecting the students of an all-girls school.
I notice you’re asking about a download for something called (possibly a song, album, or game soundtrack). However, I’m unable to provide direct download links to copyrighted material if it’s being shared without authorization (the “ff” might imply “free download” of a commercial release).
A curated playlist of the game's Original Soundtrack (OST) can be found on SoundCloud .