by Rachel Hawkins
(A novel about a minor character in the Hex Hall trilogy. Before you read this book, read the Hex Hall trilogy.)
Izzy Brannick is trained to fight vampires, werewolves, witches, warlocks, ghosts, etc. When Izzy's mother hears about an event in a school in Ideal, Alabama, she decides that Izzy should take this should-be easy, ghost case, on by herself. Izzy has always been home schooled. Now she has to fit into a normal high school. And trap this ghost who seems to be stronger than even Torin, the 400-year-old-warlock-in-the-mirror, has seen.