I have an obsession with angels. I have researched them extensively. I found a few things very clever in this book. The main thing being Daniel's last name; Grigori and the title of book mentioned in this book, The watcher. I can't say too much without spoilers but that is about the only thing that made me "squee". I am a catholic girl and any catholic girl worth her weight in salt can tell you about the order of Angels so I was really into the cleverness of it.
Other than that bit of clever-ness the book was a little slow moving for me. It moved too slow and I was like come on already and get to the big reveal. And my gawd, it didn't help that Luce was a bit daft! She is dolt, which was almost enough to make me stop mid story but once the story got going it was a lot better and thankfully I didn't stop.
The characters, excluding Lucinda, were good though and Mrs Kate did a great job on Cam. His part was perfection for who he is. Of course I loved him, no surprise there. Daniel, I also liked but he was also a bit confusing. The major problems and dragging of the story is because of HIM and his talking in circles. I was even like "huh? You couldn't explain that a little better Daniel. I know Luce is dumb but MERCY! Clear that explanation up a bit."
Besides the dragging of the story I guess it was a good angel tell. Mrs Kate did do research which I love about this story. I also love how she didn't bore us with a lot of back round info.
If you liked the characters immortal instruments series by Cassandra Clare, you will most likely like the Fallen characters.