** spoiler alert ** 
 Lauren Oliver is better than this book. 
 Okay, a little extreme, but Lauren Oliver is too good to end up with the book that this became. Sorry. 
 Some of this might be mindset thing. I'm on vacation right now. I read thrillers about upper middle class white ladies as my beach reads. Last year was when I read Gone Girl; a permanent spot on my favorites. Maybe it's because I was holding it up to the standards of Gone Girl; which I was able to predict pretty easily but still liked the trip and the commentary it took me through, maybe the similar ending of We Were Liars left a bad enough taste on my mouth, maybe it was rushed plotting because I honestly thought that the author was going through a much less resolution than the one we got, but this was disappointing. 
 Main spoiler (I can't tag now because I'm on mobile) missing sister was dead the whole time. Despite joint POV. Sister thought she was other sister. All other interactions as Dara no longer matter. Nick is just batshit insane. 
 This is the laziest conclusion she could have possibly gone with. No complexities, just a plot blurred by crazy. Crazy is something you have to be super careful with because it's overused and cliche. It's too easy an explanation. The third act was hopelessly rushed. And the ending wasn't satisfying. Especially in the romance department. It felt too forced. 
 High marks go towards prose as always for this author, and it's incredibly easily to tear through, and I did enjoy the ride until the last twenty or so pages, granted that was when things were supposed to be resolved.