When Sabriel was a newborn baby, she almost died. Luckily for her, her father is the Abhorsen, the most recent (besides Sabriel) in an ancient line of people who lay the Dead to rest--the opposite of a necromancer, in other words. Whereas necromancers raise the Dead and use them for their own purposes, Abhorsens find Dead spirits that have made their way into the world and send them deep into death, so that they will not find their way out again, and can instead rest peacefully. With his daughter dying, Abhorsen plunges into Death to save her. He is able to pull her back to Life before it is too late, but he makes an unpleasant discovery at the same time--a Dead spirit called Kerrigor is beginning to fight its way out to the living world...
Eighteen years pass, and Sabriel is now enrolled at Wyverly College, where she has been educated since she was five years old. Aside from her regular classes, she also learns magic--Charter Magic, the "good" type (as opposed to Free Magic, the dangerous and dark magic of necromancers and the Old Kingdom, on the other side of the Wall--Wyverly College is located in Ancelstierre, south of the Wall). But there are some things that Magistrix Greenwood can't teach her, and so she learns the trade of the Abhorsens from her father, who visits a little more often than the headmistress of Wyverly thinks. She memorizes the Book of the Dead, learns how to use the seven bells that can control the dead, and even does a little fighting of the Dead herself. But one night, a Dead spirit shows up in one of the school's dormitories, and Sabriel is called to deal with it. It proves to be no ordinary haunt--it's a messenger from her father, and he has sent her his sword engraved with Charter marks and the belt with the pouches for the bells. She knows what this means--either Abhorsen is dead or trapped in death, and she must save him. A journey into the Old Kingdom follows, but it is clear that much more is horribly wrong than just Abhorsen being trapped in death. Sabriel ends up with a sarcastic cat spirit named Mogget and a confused young man named Touchstone at her side, and the three of them work to save not only Abhorsen but all of the Old Kingdom and Ancelstierre, too.
Nix gets good marks for world-building! The two worlds of Ancelstierre and the Old Kingdom are fantastically contrasted and very well-developed, with every necessary detail in place. I especially liked the way that modern technology was included--Ancelstierre has cars and telephones, and also tanks, which are described as being newer inventions. Sabriel's home country could've been a bit more detailed, I felt, but not much of the book is spent in Ancelstierre, so it wasn't quite necessary. But even without a ton of detail, the country had a very specific feel to it. And as for the Old Kingdom, there again I found perhaps a slight lack of enough detail, but there was still plenty to make it believable. Sabriel is a little more plot-driven than description-driven, I think, which is not necessarily a bad thing. Besides, all of the incredible detail on the Dead, Death, necromancy, and Abhorsening (I don't know what else to call it--they don't really give Sabriel's job any specific name) is so complete and stunning that no one should really complain about the setting.
Ancelstierran names were, for some reason, incredibly fascinating to me. Most of them were similar to names that English-speaking people have, but there are slight differences to the spelling that may vary the pronunciation slightly as well. Some examples (with my belief of what their English-speaking equivalent would be in parentheses) are Rebece (Rebecca), Ila (Isla), Sussen (Susan), and Horyse (Horace). Melina Marchetta does a similar thing in her series, The Lumatierre Chronicles (I believe--hey, look, Lumatierre, Ancelstierre...possible inspiration in Sabriel?), where there are names such as Finniken (Finnegan) and Isaboe (Isabel). (Oh, and anyone let me know via the comments if I'm not spelling things right; my experience of Marchetta's work is limited to previews on my Kindle. Also, if you think that I use too many parentheses, you can comment on that, too--this is my ninth in this paragraph alone. Okay. Back to Sabriel.)
As the reader, you know as soon as you're a couple chapters in that there's some great mystery besides the ostensible problem of Abhorsen being trapped in Death. The instant that poor Touchstone arrives and has a painfully context-scarce conversation with Mogget, the presence of the deeper, underlying mystery slaps you in the face like a wet fish, and you go, "AAACK! What?!?!" desperately wanting to know what on earth Touchstone and Mogget are talking about. The multi-layered conflict drives the story so well. As the end nears and the final confrontation draws ever closer, all of the set-up and past battles with the Dead creates such an amazing mood! I don't believe I've felt as in-the-story and actually scared--despite not being a character--during the climax buildup since Christopher Paolini's Inheritance series. All of the Perimeter soldiers preparing, knowing their most likely fate, the fog rolling in, the sun going down, soon-to-be useless defenses being set up... You can't help but feel a little like a character.
Sabriel is a wonderful story in the hands of an adept author, and there's so little to complain about! Despite my usual practice of good-first-bad-last, I've taken care of the largest negative bit in my above paragraph, so there's nothing much to say here. Besides, I prefer to have the absence of a little thing niggling at me than the presence of a huge and awful thing screaming at me when I read.
In short, I would recommend this book to anyone who loves dark fantasy and has been reading way too many books by mediocre authors who don't really understand plot or character well enough to write anything very good. The themes of Sabriel do tend a little more towards older readers, so I wouldn't suggest this to under-elevens. But for the people at whom this book is aimed, you really can't go wrong, no matter what my acquaintance Hero says (anyway, there's always the cool title if you don't like anything else).