How It All Goes Down
Baby Sabriel makes a dramatic entrance into the magical world of the Old Kingdom by immediately dying at birth. The end.
Just kidding—though her story would be incredibly short were it not for her father, the Abhorsen.
The Abhorsen is a necromancer, which basically is a wizard who deals with death. He has the power to walk into Death itself, and send people into (and out of) Death's alternate plane of existence. So although Abhorsen can't save Sabriel's mom, who died during childbirth, he ventures into Death to retrieve baby Sabriel from the clutches of a monster in Death's quite literal icy river. Somehow we get the feeling this isn't the last time we'll see Kerrigor, the monster who disappears deep into Death to leave baby Sabriel very much alive.
Eighteen years later, Sabriel has grown up to be a successful student at Wyverley College in a place called Ancelstierre. In contrast to the land of the Old Kingdom, which is ruled by Charter Magic, Ancelstierre is a lot more like early 20th-century England—think swords and sorcery vs. guns and electricity.
When Sabriel's father misses their standing date for a magical long-distance chat though, Sabriel starts to worry. That night, a creature from Death arrives at Wyverley and delivers the Abhorsen's most prized possessions to Sabriel: a set of necromantic bells and an enchanted sword. Taking this as a sign that her dad is in bad trouble, Sabriel leaves school the next day to travel beyond the nearby Wall and into the Old Kingdom in search of her father.
At the Wall, commanding officer Colonel Horyse remembers Sabriel's dad and lets her cross the heavily guarded Wall into the snowy, uncharted land of the Old Kingdom. Maps of the Old Kingdom aren't the kind of thing you can pick up at a nearby service station, so Sabriel knows she needs to visit Death in order to summon a spirit guide, who can direct her to Abhorsen's House.
The Old Kingdom has magical nodes called Charter Stones, which are kind of like Wi-Fi hot spots for magic. Sabriel, who's been taught necromancy by her father, plans to visit a broken Charter Stone, which should give her easier access to Death.
When she gets there, Sabriel realizes that the stone was broken because a Charter Mage—one of the Old Kingdom's powerful, practicing wizards—was sacrificed on the stone, further evidence that evil is afoot. Sabriel also realizes that it may not have been such a great idea to seek out a broken stone, because some seriously creepy things have wandered out of Death because the stone is broken. After defeating one of these creepy creatures, Sabriel hits the road as fast as she can, because she spots something even worse: a Mordicant, one of the Greater Dead.
With the Mordicant in hot pursuit, Sabriel barely makes it to Abhorsen's House, which is on an island in the middle of a rushing river. (This makes it a safe haven from most Dead creatures, who can't cross running water.) There she meets Mogget, a mysterious talking white cat who claims to serve all Abhorsen. Mogget addresses Sabriel as Abhorsen, insisting that Sabriel's father is gone, making Sabriel the heir to the title. As the Abhorsen, it's now Sabriel's job to protect the Old Kingdom by sending dead things back to Death where they belong.
Speaking of dead things, there's the issue of the big dead thing waiting for Sabriel across the river from Abhorsen's House. While Sabriel's been recovering from her harrowing trip, the Mordicant has called on undead slaves to build a bridge across the water out of coffin dirt. Oh goodie. Before the Mordicant succeeds, Sabriel casts a spell to flood the river and wash away the bridge—then, newly outfitted in traditional Abhorsen garb, Sabriel escapes the flood with Mogget in an enchanted plane called a Paperwing.
Sabriel's not so great at flying enchanted planes, and they nearly crash, but Mogget gives Sabriel a ring, and instructs her to release him from the collar that keeps him in cat form. Turns out Mogget's actually a super-powerful Free Magic spirit who's strong enough to save them from crashing… but can't quite keep them from skidding into a huge hole in the ground nearby.
Also, in his true form he really wants to murder Sabriel, which is inconvenient, especially since Sabriel is now stranded at the bottom of a giant hole with a broken plane. Thankfully, Sabriel figures out that Mogget's ring turns him back into a cat, so he doesn't get to murder her after all.
Near-death crisis temporarily averted, Sabriel sets out to explore the sinkhole. In one part of the hole she finds many grounded ships, including one with a strikingly lifelike male nude on the prow. Sabriel senses that this figure is actually someone trapped in Death, and she risks a trip into Death to drag him out and save him.
When the young man wakes up, he reveals that he's been frozen for over two hundred years, and seems traumatized by guilt over events in his past. Mogget recognizes him and nicknames him Touchstone, after a jester in a Shakespeare play. Touchstone, a capable fighter and Charter Mage, pledges loyalty to Sabriel, who isn't so sure what to think about this two-hundred-year-old mystery man. Touchstone remembers a way out of the hole though, so they resume Sabriel's quest.
They follow Charter Stones to the nearby town of Nestowe, which is crawling with Dead things; the people of the town have fled to an offshore island. Sabriel and Touchstone defeat an evil Dead parasite who's been plaguing the villagers, but Sabriel senses that the Mordicant, clearly controlled by Kerrigor, has once again picked up her trail. She asks the grateful villagers for a boat so she can leave the island and lure the Mordicant away from the village, and Sabriel, Mogget, and Touchstone set sail up the coast, bound for the capital city of Belisaere.
On the boat, they are free from the restrictive spells on land that prevent anyone discussing the Charter. Touchstone and Mogget start talking, and Touchstone reveals that he witnessed a plot by a prince named Rogir to murder the royal family and break the Charter Stones in the capital city. Touchstone believes himself to be partly responsible, since he couldn't defeat Rogir—who claimed to already be dead—during the battle.
Instead Touchstone went berserk during the battle and murdered two guards, after which the Abhorsen froze Touchstone for two hundred years. Kind of an odd punishment—but maybe it wasn't a punishment? Touchstone's past remains a question mark.
The capital of Belisaere is still a bustling city despite the fact that the kingdom has fallen into anarchy. Sabriel, Touchstone, and Mogget stay in an inn and plan to visit the underground reservoir where the Queen was killed, thinking that it's likely Sabriel's father is trapped by the cracked Charter Stones there.
They make it out of the safe part of the city and into the reservoir, which leaves them vulnerable to attacks by Dead creatures—and just as predicted, Sabriel finds her father's body there, still standing in a protective diamond of magic, but trapped in Death.
With Touchstone and Mogget standing guard, Sabriel casts another protective spell around her father's spell, and enters Death to look for him—she is tempted to kiss Touchstone before she goes. Touchstone and Mogget wait in fear as the noise of an army of approaching Dead creatures gets louder. The creatures are heralding the arrival of Kerrigor, which is really bad news.
Sabriel finds her father trapped deep in Death, and is only able to free him temporarily—he's been trapped in Death for too long to come back to Life permanently. He explains that he froze Touchstone onto the ship because Touchstone is the last surviving royal prince. It's maybe not so good that Sabriel freed Touchstone, because now Kerrigor can continue his quest to completely destroy the Charter by sacrificing someone with royal blood on the Charter stones. Whoops.
Sabriel's father instructs her to grab Touchstone and get out of there, and takes her sword and one of her necromantic bells to ward off Kerrigor. When Sabriel and her father make it back to Life, Kerrigor is about to attack—Sabriel and Touchstone escape though, avoiding the siren call of Sabriel's father's deathly bell with a well-timed kiss. Sabriel's father succeeds in banishing Kerrigor temporarily with the bell, but dies in the effort.
Touchstone goes a little bit berserk and carries Sabriel to meet two sisters called the Clayr, on Sabriel's father's instructions. The Clayr are visionaries and show Sabriel the location of Kerrigor's body—if Sabriel can lay Kerrigor's body properly to rest with necromancy, Kerrigor will be defeated. Kerrigor's body is hidden in Ancelstierre, not far from Wyverley College.
The Clayr have a Paperwing ready for Sabriel and Touchstone, and the two of them take off for the Wall. When they get there, they tell Colonel Horyse about Kerrigor's body, and Horyse gathers a group of soldiers to help with the effort to destroy Kerrigor.
Back in the mostly-magic-free land of Ancelstierre, Sabriel identifies the spot where Kerrigor is buried, but even with the help of the soldiers, she can't open the sarcophagus—she needs more magical power. Sabriel realizes that the older magic students at nearby Wyverley College may be able to help, so the military hauls the coffin to Wyverley.
Meanwhile, power outages and encroaching fog signal the arrival of Kerrigor and his newly assembled zombie army. As the soldiers open fire against the zombies, Sabriel prepares the students to help open the sarcophagus. Joining hands in a circle, Sabriel, Touchstone, students, and soldiers open the coffin together, but just as it's opened, Kerrigor and Mogget, in Free Magic form, crash into the room.
A huge fight breaks out and Touchstone's leg is injured. Mogget delivers the Abhorsen's sword and bell back to Sabriel, but then hurls himself onto Kerrigor and vanishes.
Sabriel destroys Kerrigor's body using the final bell, then ultimately traps Kerrigor using Mogget's ring. In a completely bizarre twist, the ring transforms Kerrigor into a black cat, and then Mogget appears in white cat form next to him, apparently intact. But right before Kerrigor is transformed, he stabs Sabriel, and she dies. You heard it right: our hero actually dies.
As Sabriel gives herself up to the icy river in Death, she hears the voices of past Abhorsen, including her father, telling her that it's not her time to go. They send her back to Life, and she wakes up in Touchstone's arms.