This is, I think, my least favorite of the books in this trilogy. I don’t know why, because I like the character of Will, but there you have it.
Ok, if you’ve read the first book (The Golden Compass) you know that Lyra is the hero, and she’s from an alternate world where people’s souls live outside their bodies as animal daemons. Her mother, Mrs. Coulter, is trying to find Lyra because she’s part of a prophecy. Lyra went to her father for help, making friends with the witches and the king of the bears. Her father made a gateway between worlds and she followed him, finding herself in a new world.
Will, meanwhile, accidentally kills some home intruders and flees his home. He finds a hole in the air and he goes through it and finds himself in the same alternative world as Lyra.
They meet up and go back into his world where they get more information about the “dust” that Mrs. Coulter has been studying, which researchers in Oxford have been studying under the name “dark matter.”
While they’re there, someone steals the alethiometer that Lyra has been using to guide her quest. Will goes to get it back and the thief offers to trade it for the subtle knife, which is in the world where Lyra and Will met.
They retrieve the knife, but Will loses two fingers in the attempt, which indicates he’s the knife’s new guardian. The knife can cut between worlds and cut anything at all.
Mrs. Coulter finds and kidnaps Lyra and Will sets out to find her.
This is a massively popular series, and it’s well done. I’m not as much of a fan of this as I am of other fantasy series, but it’s still good.