Well, this is one of the weirdest and also most fascinating books I've ever read. You become immersed into a dream-like state when reading it - you have to just let the author take you along. It's excellently written, but somewhat difficult. If you understand music, this novel will be much more enjoyable for you.
In a nutshell: The (female) friend of a (female) elderly Danish composer inherits the composer's last and unfinished work , and by trying to finish the opera, finds out about her older friend's life.