"I am doing Half-Blood Prince, and I'm doing it because I love the world, I love the characters. I think I have more business with this world and these characters. I've made a kind of tonal shift with the fifth film, which I want to continue and develop into the sixth film, and I can see the fifth story evolving into the sixth story in a really interesting way. So I'm on a journey with this material and this world, and I'm keen to complete it."