Lyra Belacqua is a carefree child, running around the town of Oxford and making mischief, terrorizing the Scholars at Jordan College, etc. She does so with her friends and her daemon, Pantalaimon. That is, until she witnesses the Master of the College trying to poison her “Uncle Asriel”. Shortly after she prevents his poisoning, the beautiful and intelligent Mrs. Coulter comes to Jordan College and takes Lyra away. Initally wanting to spend much time with Mrs. Coulter, Lyra takes little time to realize that Mrs. Coulter is behind a string of kidnappings happening all around the country. Upon this realization, she runs away.
After escaping, she is found by some gyptians, whom she knew while she was at Jordan College. The gyptians tell her that her Uncle Asriel, Lord Asriel, is really her father and that Mrs. Coulter is her mother. She ends up being brought along by the gyptians as they plan to head to the North, where the kidnapped children are reported to have been taken. The plan is to rescue them. Upon arriving in the North, the gyptians acquire help from both Lee Scoresby, a balloon pilot, and Iorek Byrnison, an oucast armored bear. The armored bear would be very helpful as the expedition to free the children heads further north into the polar lands – a land easily navigated by bears.
They eventually arrive at Bolvangar, where they learn that Mrs. Coulter and her accomplices have been experimenting on children and severing their links with their daemons – a very cruel deed, indeed possibly the cruelest, as a daemon is half of one’s soul. Lyra with everybody else’s help, including that of a witch clan, rescues the children and flees from Mrs. Coulter again. This time she flees via Lee Scoresby’s balloon with Iorek, the witches, and her friend Roger whom she had rescued and they head further North to Svalbard, the land of the armored bears, to rescue a captive Lord Asriel. Before arriving they are attacked and Lyra ends up a captive of the armored bears. She cons their king (and Iorek’s brother) into fighting Iorek in a life-or-death battle. Iorek wins and takes Lyra to see her father, Lord Asriel.
Lord Asriel tells Lyra about Dust, the thing which he has been studying extensively and which is the subject of much speculation and derision by the still-powerful Catholic Church. He also tells her of the cities and alternate universes on the other side of the Aurora Borealis and how he means to reach there. As she sleeps, Asriel steals Roger away. As soon as Lyra finds out, she starts to chase after Asriel with the help of now King Iorek. After a short delay wherein Iorek and his accompanying bears are set upon by witches and Mrs. Coulter, she catches up with Asrael. Unfortunately, she’s too late as Lord Asriel severs Roger’s daemon connection in order to create a bridge to the city behind the Aurora. In the end, Lyra follows Asriel across the bridge into the city in the sky.