I feel like I missed part of Lucy's story that everyone keeps referring back to her kidnapping, rape and almost murder but you as the reader don't know the full story. There was a full investigation that has happened before this book that I did not know anything about. I feel like there was another book that I should have read before this one, I think it might be in one of Brennan's other series. For a standalone read (or beginning of a new series) there was a lot of reference to another book and events that the reader knows nothing about.
From what I learned about Lucy in this book I really liked her as a main character. She has not let the events that happened in her past control her, yes they have changed her, but she is a fighter and knows what it takes to survive, especially when she is tested. It was interesting how she wanted to become an FBI agent but also spent her free time trying to catch online predators (think of to catch a predator minus the TV part of it). This was an interesting aspect to the book with perpetrators being murdered, but once again when this part of the mystery works out, you realize that this too relates to a previous book that Brannan has written (I think).
The serial killer in this book is very sadistic and want to control every woman out there. He thinks that they need to be molded into the perfect woman and are only there to serve men. If they disappoint him too much or if they do not learn his rules he will kill them. There is also some mention that he may sell some of his "perfect" women off but this is not fully stated, explained or explored. He does torture the women in the book, and these scenes were fairly sadistic and deeming to the women in this story.
Brennan had some ideas here that had great potential to make this book into a true mystery and thriller, but these aspects were greatly overshadowed by Brennan's need to have the relationship between Lucy and Sean front and center. I think I remember now this is why I stopped reading her books. Additionally, I think that Brennan referenced too much back to books of hers that I had not read, something I do not expect when starting a new series. Oh well at least I gave her a try again, but I don't think I'll read another of her books, they are not for me.