I started reading this book knowing that it was intended for a young audience, and that wasn't a problem because I can judge different books accordingly and taking into account the intended audience. It's an entertaining book, but it was a bit boring at some parts and it was way too long. If it made me think it was too long, imagine what a teenager would think while trying to read the book. The story and the message are clearly religious, with lots of religious elements, but it also mixes magic; that makes of the story cuter, but at the same time I think it can get too messy.
The plot is interesting: Audie is a girl who suddenly discovers she is an angel, and not a regular angel, but a very special one. I won't include spoilers, but I will say that she may have an important role to save Heaven from an immediate menace. Audie and an army of other angels who have different powers will try to get to the place where they may find something that will save Heaven from being destroyed.
The characters are described in a way that will make any teenager get hooked or sympathise with them. However, they didn't made me get more engrossed in the story. I found some of them tiresome, especially Cave. Cave is the narrator of the story, since he is the only human in the group and he is in charge of writing the Archives. His instant crush on Audie and the way he talks about it is a bit ridiculous and made me roll my eyes quite a lot. It's impossible to feel sympathy or relate to him.
Entertaining story for teenagers, although I would recommend that the book gets one more edit. Poor edition makes reading difficult sometimes and it makes it more difficult to feel engaged in the reading.