When I started this, I could tell I wasn't that into it, but since I had enjoyed the previous books, I figured I'd give it a shot. The book did not improve from its beginnings.
First of all, I couldn't believe the not able to sleep/staying up as long as she was situation. That much sleep deprivation would drive a normal person insane, that's why there's a reason that sleep deprivation has been used as a torture technique. If Reyes cared for her, he would try to fight going into Charley's dreams, instead of being angry that he's there in the first place. Just cause he's ticked off at being bound does not give him the right to be angry at Charley for everything she does. I get that he wants revenge, but there are other ways of doing it besides assisting something that can ultimately kill her.
The investigation was pretty weak overall. There wasn't much actual investigating done at all! It felt like it was just thrown in there to fulfill a page requirement. The underwear fixation did not mesh well with the rest of the book, either. While it may have referenced the lustful feelings, it just felt icky to me. I also didn't understand her motivation for her actions. The conversations she had with the people around her offer a chance to explain her actions, but since she keeps sidestepping, it becomes missed opportunities. The only thing I can think to explain it is that her sleep deprivation actually made the sidestepping make sense to her.
Overall, it wasn't an enjoyable read for me.