CODA is a book about music. A drug that many people in the world use, but most don't think of it in that way. Music is a way of life, but when it is used in the wrong way it can be harmful. In the book music is played in clubs and on consoles in the home. In their world it is used as a drug to control emotion, kind of the way alcoholics use alcohol. Music is seen from a whole different perspective when reading this book. When Anthem (the main charachter of the book) decides to go against the law and play un-encoded music the life of his friends and family are at risk. He manuvers around various obstacles to attempt to save the lives of his younger siblings (Alpha and Omega). When the girl he loves ends up being the solution to his fight it is a struggle for him to trust her to get the job done.