I realise this book is a few years old now but it was recently recommended to me. I was absolutely gripped from start to end and thought it was brilliant. However I've just read a few reviews and was surprised to see so many 2/3 stars because readers were disappointed with the big reveal at the end (reason Nina hated Emma). I thought it made perfect sense that something seemingly trivial would drive Nina to such lengths as she was obviously mentally disturbed.
Anyway, I'm off to find Lane's first book which I haven't read yet and am told is just as good!