Book One.

A war is brewing in Lyra's world--a battle between those who would keep people in ignorance and those who are willing to fight for true freedom. Lyra is thrust into the middle of the conflict when her uncle Asriel comes to Oxford, fomenting rebellion, and when her best friend, Roger, suddenly disappears.

Lyra learns that Roger was kidnapped by a shadowy organization that steals children and, it is rumored, experiments on them. To find him, she will travel to the cold, far North, where armored bears and witch clans rule . . . and where her uncle Asriel is attempting to build a bridge to a parallel world.

What Lyra doesn't know, mustn't know, is that her actions will have consequences not just in her world, but in all the worlds beyond.