A speculative fiction novel. The main character is an author, and her family knows a strange guy who takes existing stories and uses a code to make songs out of them. The guy starts messing around with her stories and is soon responding to her fans pretending to be the other.
It doesn't have an ending. It's one of those experimental novels that doesn't make sense and has a cliffhanger.
(Yeah, it didn't make sense to me, either.)