The Amber Spyglass is the conclusion of the His Dark Materials Trilogy. It follows in The Subtle Knife and Northern Lights and takes place in many other universes. The story is about the love between the Protagonists, Lyra and Will, as well as some difficult decisions they must make. A great new universe added to the story is one with strange creatures called Mulefa and Dr. Mary Malone's development of her beliefs about what Dust is and how the world works.