And by the way, I read this a few years ago and forgot what it was called. I have just found it again now. And this story actually introduced me to Rachmaninoff's second movement of his piano concerto number two, which is just the most haunting piece ever.
This was one of the most beautiful fanfictions I have ever read. I love it! I ended up googling Carrer Del Vicari Joaquim Fuster in Palma, Illes Balears and the esplanade shown in street view was just how I imagined the place to look in the story, even the buildings. A lot of fanficions are badly writen or ruh things, or are just plain sex and stuff but I love how things work out in this, not rushed at all. It's so perfect that it could almost have happened.