Will is twelve, and he's just killed a man. Now he's on the run, determined to discover the truth about the father he's never known.

Then he steps through a window into another world - where soul-eating Spectres haunt the streets of a city, and a strange girl called Lyra is searching for Dust.

His mission and hers are mysteriously linked, and together they must find a powerful and secret object that people from many worlds would kill to possess.