Sabriel by Garth Nix

"Sabriel" is the story of a young necromancer who sets out to save her father, who has been trapped in the realm of death. Now when you see the word "necromancer," don't start conjuring up the typical images and tales associated with that term. This book is not about some teenage girl soaked in dark magic who raises the dead to have them do her evil bidding. Or even to cause teenage mischief.

Sabriel is the last in a long line of Abhorsens. The Abhorsen is a title given to a necromancer who's job is to fight evil, and to make sure that those who should stay dead do so. Sabriel knows a little bit about this because her father was the last Abhorsen, but while he trained her as a necromancer in his infrequent visits to her school, he never really prepared her mentally to one day take his place.

Now the Abhorsen, Sabriel's father that is, is stuck in death. Sabriel doesn't know how he got stuck there, and she has very little clue as to the big picture either, but she sets out from her boarding school in Ancelstierre to set her father free. To do this she leaves her safe world, and in many ways her child hood, and travels into the Old Kingdom where magic reigns and evil walks.

Sabriel quickly realizes that there is a lot more going on than her father simply being trapped. She also finds herself being addressed by the title Abhorsen, something that both frightens her and catches her completely off guard. She makes some dubious alliances with a cat named Mogget and a young Charter Mage named Touchstone, and it will be up to them to hold the darkness at bay that is threatening to destroy what fragile peace and hope is left in the Old Kingdom, not to mention invading and destroying Ancelstierre.