Angels called Watchers took human wives and produced offspring. The Watchers were then imprisoned. They are all uncaring and evil. People who study these creatures and who are at war with the offspring in order to save humanity are call Angelologists. The book reminded me a bit Dan Brown with Angels. I didn't love it, but found it interesting. I think there will be more books and possibly a movie. I will probably have to read them all and see the movie, though.