Conjuror by John Barrowman
Imagination is a powerful thing.
There are three things in this world that seventeen-year-old Remy would guard with his life: his gold pendant, his blues harmonica and his mother's journal. This is all he has left of his murdered family. And he believes these objects will lead him to their killers.
Remy can't hunt them down alone. He needs Matt and Em Calder, twins who can bring art to life and travel through paintings. For, like them, Remy has supernatural powers. He is a Conjuror, descendant of an ancient bloodline that can change reality with music.