his discovery that Dust at the North Pole links to infinite worlds. He is granted another expedition though his theory, if proven, could undermine the Magisterium's control. Mrs. Coulter, a wealthy "friend" of the college, invites Lyra to stay with her in London. The Master of the college entrusts Lyra with her uncle's alethiometer, a compass-like artefact that reveals the truth, warning her to keep it secret. Kidnappers called "Gobblers" have been abducting children, including Lyra's friend Roger and Billy Costa, a young Gyptian. Lyra discovers Mrs. Coulter is head of the General Oblation Board, realising they are the Gobblers, and she and Pan escape when Mrs. Coulter's dæmon attempts to steal the alethiometer. Lyra is saved from Gobblers by Ma Costa, Billy's mother, and taken to the Gyptian king John Faa, who is sailing north to search for the children. Gyptian elder Farder Coram recognizes the alethiometer, which Lyra discovers she can decipher. In league with the Magisterium, Mrs. Coulter sends mechanical spy-flies after Lyra, but one is caught by Farder Coram. Asriel reaches Svalbard, the kingdom of the Ice Bears, but is captured by Samoyed tribesmen hired by Mrs. Coulter. The witch queen Serafina Pekkala tells Lyra the children are at Bolvangar, and Lyra befriends Texan aeronaut Lee Scoresby, who suggests she hire him and his friend Iorek Byrnison, an armoured bear he has come to rescue. Once a prince of the bears, Iorek was defeated and exiled, and the townspeople have tricked him out of his armour. Lyra uses the alethiometer to help Iorek recover his armour, and he and Scoresby join the Gyptian trek northward. Lyra, astride Iorek, follows the alethiometer and finds Billy, whom the Gobblers have experimented on using "intercision", a procedure that surgically separates him from his dæmon. The Gyptians are attacked by Samoyeds who capture Lyra, with Iorek and Lee in pursuit in Lee's airship. Lyra is taken to the bear king Ragnar Sturlusson, and tricks him into fighting Iorek himself. Ragnar, who poisoned Iorek's father, has the upper hand until Iorek feigns weakness and kills him, reclaiming the throne. Iorek carries Lyra to Bolvangar, but she is forced to cross a narrow ice bridge alone before it collapses. Reaching the experimental station, Lyra reunites with Roger, and overhears Mrs. Coulter say that Asriel will soon be arrested for heresy. Caught by the scientists, Lyra and Pan are thrown into the intercision