Tark is having a rough time of things--he's adjusting poorly to the move, but more than that, he's adjusting poorly to having his mom (who has tried to kill him several times) in a psychiatric hospital, and he's adjusting poorly to seeing that evil ghost pop up and destroy everything near him, and he's adjusting poorly to that other ghost--the woman in white--who's also been hanging around. That demon spirit is somehow trapped inside him, and the bindings are growing weaker. 
 This was sufficiently creepy but I wanted scarier. (When it comes to books, I always want scarier.) The whole story is told from White Ghost's POV, and while she's some kind of vengeful spirit killing child murderers, she's mostly an observer. 
 I liked this. I can think of a couple of kids I'll suggest it to. I wanted more, but I'm an adult--I'd have loved this when I was 14, I'll bet.