Hedge Witch The Cloven Land Trilogy, Book 1

Fifteen year-old Cait Weerd has no idea she's being sought by the undain: sorcerous creatures that feed off the spirit of the living. She doesn't know they need her blood to survive. She doesn't even know she's a witch, descended from a long line of witches. Cait Weerd doesn't know a lot, really, but all that's about to change. At Manchester Central Library she's caught up in sudden violence. In the chaos she's given an old book that's been hidden there. Given it and told to run. Hide the book or destroy it. The book contains all the secrets of the undains' existence. They and their human servants want to find it as much as they want to find her. Cait learns the fates of two worlds are at stake. Just what she needs. Along with definitely-not-a-boyfriend Danny, she has to decide what the hell to do. Run, fight or hope it all goes away. It's only then she learns who she really is, along with the terrible truth of what the undain have been doing in our world all this time...