An important part of the story is that, in the world in which it takes place, every single person is accompanied at every moment by a familiar spirit, literally called a “daemon,” that takes the shape of an animal corresponding to their personality. The main character’s daemon is actually named “Pan,” the name of the Greek goat god upon which the trickster initiator archetype is partially based. In The Golden Compass, with children, the daemon is able to shape-shift into different animal forms until the individual’s core personality has solidified.
During this transition period, it is revealed that the children are vulnerable to “attack” from the pernicious influence of the Dust. The meaning of this is unclear, but is of great concern to the evil empire that rules this fictitious world, called the “Mysterium.” They are believed by the main character, Asriel’s niece Lyra, to be behind the theft of children that has been plaguing the orphanages and underclass families of the land. Lyra sets off on a quest to solve the mystery of these disappearing children, rumored to have been captured by enemies called “Gobblers.”
To aid her in this quest, Lyra makes use of the “golden compass” referred to in the film’s title, which is actually called an “alithiometer”: a divination device for detecting truth. It looks like a large pocket watch, and contains wheels with strange emblems on them, which it uses to communicate oracles in answer to questions. In reply to these queries about the kidnappings, it points to images of a baby and a pot boiling over a fire.
Lyra later discovers that the children are being used in experiments in which they are permanently separated from their daemons, supposedly so that they can “grow up” properly. In fact, it drains them of vitality and ends up killing them. In the original book, it is revealed that Lord Asriel is in fact conducting similar experiments at the North Pole.
It turns out that Lyra’s whole quest has been a ruse all along, devised by him. His purpose was really to lure Lyra and her friend Roger to his polar laboratory. There, he separates the boy from his daemon and used the energy generated by this to power an inter-dimensional portal machine that he has invented. So instead of just looking for a portal, he created his own, ripping a giant hole in the atmosphere at the top of the Pole.
This story is rich on many levels, as are the other books in the series. The second part is called The Subtle Knife, which refers to a tool that can cut a window between dimensions (and can cut through anything else as well). This is the “Good Sword” archetype I wrote about in the Film Myth Analysis Thesis.
The location of the portal in Philip Pullman’s novels indicates that the author has knowledge of the nineteenth and twentieth-century stories of secret entrances to a hidden underworld at the North and South poles, where supposedly could be found the so-called “Black Sun.” This is a development of the more ancient concept of the hidden sun at the center of the Earth which is said to light the tomb of the sleeping god-king (or goddess-queen) of the fallen kingdom.