Odd's monastery retreat is rudely interrupted when bodachs begin appearing in the school attached to it, hovering around the disabled children the nuns care for. The threat isn't a person, but a new kind of monster, a being born of nature, the supernatural, and a deeply-held hate that threatens to destroy everyone. 
 For the most part, Koontz backs up from the extra supernatural possibilities he'd introduced in the last book and brings it back to Odd and his ability to see ghosts and bodachs. The monster, though not a ghost or a person, is a once-off sort of thing, and once the person at the heart of the mystery is defeated, the monsters also disappear. It's a nice way to keep things interesting while still keeping them simple. 
 The dialogue has gotten odd (heh) in this book; there are now several people who talk just like Odd, and the conversations they have with each other are really strange. 
 The atmosphere at the end of the book contained some interesting shadows of Sphere, which added some (possibly unintentional but still interesting) intertextual depth for those who have read Sphere.