After three books, Anthony Horowitz, the central character in Anthony Horowitz’s The Twist of a Knife: A Novel splits from ex-detective Daniel Hawthorne. He has a new play opening in London’s West End to attend to. But when Sunday Times critic Margaret Throsby pans the production and then winds up stabbed in the heart with a dagger that belongs to Horowitz, he becomes the prime suspect. Does anyone know a good detective? Joining to moderate is Dwyer Murphy, author of An Honest Living.