School Spirits by Rachel Hawkins
Izzy has spent her life hunting and fighting monsters (vampires, ghosts, demons, etc.) with her mom and sister. But sister went missing on a mission, so Mom decided that an easy hunt, where Izzy can spend some time as a “normal” teen would be a good idea.
This story had things I liked about it: Torin, trapped in the mirror; Izzy, though a misfit, finds real friends; and Dex, who is sure of himself in his uniqueness. But there are small plot issues that stuck with me. If they moved to a different house for this mission, how is Izzy able to go into her sister’s room, to look at stuff? Did they move sister’s stuff? That doesn't make sense to me. They aren't planning on staying in this house. That said, I probably won’t work real hard to get the next one before my students.