The epic love story. Let's face it. The thing that really makes this series so amazing is the love between Ellie and Will, her guardian. Sure, there is danger and mystery and death and destruction and the potential end of the world. But it is Will's overwhelming love for Ellie and his desire to protect her in all things, and Ellie's love for Will and her desire to be with him despite all warnings against it ... that is what makes this story epic in my mind. I LOVE Will as a character. So much. As amazing as his love for Ellie has been in the first two books in the series, I was able to see the power of that love even more fully in this novel. But that love becomes a hindrance at a certain part of the book, and Will and Ellie have to decide if their love is bigger than the fate of the rest of the world. They definitely have to struggle with this a bit when it becomes clear that one of them might not make it through the attempt to save humanity. 
 Cadan! 
 Oh Cadan, I have to apologize to you. You were just so amazingly awesome in this book as you did all that you could to help Ellie find a cure for the man she loves, doing this despite your overwhelming love for her. You helped Ellie at every turn. But I have to admit that as I was reading I was starting to worry that it was all going to end up being some big hoax, that I would find out that you were really working against Ellie and still working for the demons the whole time. I didn't want this to happen. I was going to be really, REALLY upset if this happened. But because I worried that you were going to abandon Ellie in the end I kept my heart guarded for this entire book because I did not want to have it torn out of my body and squeezed to death right in front of my eyes. So I'm sorry. I was just as bad as almost everyone else in this book who didn't put all their faith in you. Luckily, Ellie did. 
 All I can say is ... CADAN IS FREAKING AWESOME!!!!!! I loved this character so much. He may be my favorite of the whole series, even though I was always Team Will when it came to Ellie's heart. Still, Cadan was such a contradiction in a world of extreme black and white reality. I wish that there could be a spin-off series involving him because I still want to know so much more about him. And seriously ... this boy deserves a Happily Ever After romance. Seriously. 
 The themes of this book were wonderful. I love books that make me think. Ellie's connection to her humanity allowed her to feel emotions, a thing that did not affect other angels. Angels were meant to be soldiers, beings who obey without question and without emotion. But Ellie's humanity allowed her to feel things like remorse and love. The angels believed those emotions to be weakness, but Ellie finds that to be her greatest strength. And then there is the issue of whether it is better to sacrifice your own happiness and life in order to save others. It might be easy to make that decision on a theoretical level, but a bit harder when there are others left behind who will suffer when you are gone. 
 The ending was perfect ... but I kind of wish that it was maybe two or three pages longer. I wanted to know more. I wanted more Will and Ellie. Still, I don't know if there could have been any more perfect ending line for this series than the one Courtney chose. Brilliant. 
 There is death in this story. There is the pain of loss. But that has been par for the course in this series. People are going to die in this struggle between good and evil. There are times in this book where I could not read fast enough. I needed to know what happened next. The good thing is ... Good prevails in the end. Love totally conquers all! Yay for that. The ride I was taken on to get to the satisfying ending was well worth my time this week. I highly recommend this book as a fitting conclusion to a wonderful series. You won't be disappointed. Four stars!