Inspiration: I play a lot of instruments IRL and I just bought a new little flute thing.
I don't have a main plot, just some kinda disconnected ideas that I think with help could turn into a pretty cool RP.
-Supernatural stuff exists, it's just hidden from most of the world
-Music is unique in that it's a distinctly Human thing in this setting, no gods nor angels nor monsters have any ability to really write or really play music. Sure, they can hear it, if they pick up the instruments and practice they might be able to imitate the sounds accurately, but they can't play from the heart like humans can- and that's where music gets its power.
-These days, now that most of the need for magical music doesn't exist anymore (thanks to the efforts of individuals like the Pied Piper who eliminated the Rat Kings hundreds of years ago), nobody really knows that music is capable of actually being magical
-There are a select few who discover that they have the ability to perform simple magic through their music, even if they aren't particularly good at the instrument. Perhaps they picked up their buddy's base guitar while drunk, idly plunked around on the strings, made something that almost sounded like a tune for a bit, and without realizing it shielded the house they were in from an earthquake. Their powers only grow as they improve on the instrument.
Plot would likely be something along the lines of supernatural horrors being on the rise, and the characters needing to use their powers to fight back. The RP would likely involve a lot of song links, and if you aren't playing a wind instrument then you'd be free to rewrite lyrics to fit what's going on.
Any takers? If we do this, I call the fiddle.