At a northern port, Lyra is befriended by a Texan aeronaut named Lee Scoresby. He advises her to hire him and his friend Iorek Byrnison, an armoured bear that Lee has come to rescue. Once a prince of the armoured bears, Iorek is now exiled in shame, the local townspeople having tricked him out of his armour. Lyra uses the alethiometer to locate Iorek's armour. After recovering it, Iorek joins the Gyptian trek northward, along with Scoresby. Lyra, astride Iorek, goes to an abandoned building the alethiometer pointed her toward. There, Lyra finds Billy Costa, who has been surgically separated from his dæmon. The Gobblers are experimenting on the kidnapped children using a procedure called "intercision." Lyra reunites Billy with Ma Costa, but the group is attacked by Samoyeds, who capture Lyra. Iorek and Lee follow her in Lee's airship. Lyra is taken to the bear king Ragnar Sturlusson. Knowing Iorek will be outnumbered, Lyra tricks Ragnar into fighting Iorek one-on-one. Ragnar, who usurped Iorek's throne, initially appears to be winning Iorek feigns weakness and kills Ragnar, avenging his father and regaining his kingdom. Iorek carries Lyra to Bolvangar, but only Lyra crosses a narrow ice bridge before it collapses. Upon reaching the station, Lyra reunited with Roger. Coulter telling the station scientists that Asriel escaped and has set up a laboratory. Magisterium soldiers are going there to arrest him for heresy. Lyra discovers scientists are experimenting to sever a child from their dæmon. Caught spying, Lyra and Pan are thrown into the intercision chamber but Mrs. Coulter tells Lyra that the Magisterium believe intercision protects children from Dust's corrupting influence.