Black Heart Blue follows the lives of two sisters and there are two parts to this book, the first half is split into before and after chapters. Before is told by Hepzibah and the after is told by Rebecca, I really like reading about Hepzibah as it meant you could learn things that her sister didn't know. She was slightly strange in the sense that she wouldn't want Rebecca near her in public and that she would occasionally get annoyed with her, her feelings were very mixed but she did care about Rebecca but just because she could practically live a normal life unlike her sister she wasn't in my opinion the strongest out of the two. Rebecca has Treacher Collins which meant the bones in her faced weren't properly formed whilst she was in the womb, this meant constant stairs and no friends for her at college. At the beginning Rebecca does live in her sisters shadow but as the story progresses she becomes stronger even if she doesn't realise it herself. As the sister with a syndrome she was constantly picked out by her father because she was some sort of sign of the devil, or that's what I can remember anyway. One thing I noticed about the two sisters was that they both referred to their parents differently, Rebecca's way of referring to them definitely sent chills down my spine. Instead of my Dad or Mum , it was The Father and The Mother making them almost seem alien.Throughout reading this book I couldn't help but think that Louisa sometimes had a very poetic way of writing things, this book just seemed to flow and the descriptions were so very fantastic and vivid I found myself living a life I could never even imagine. I wouldn't say this is something you could read if your looking for something light for the summer, but I would totally recommend it to anyone who wants to read something a little different from what they're used to. This story also keeps you hooked from beginning to end and there is never a dull moment, Louisa added just the right amount of mystery and suspense to keep me going and although there were tiny hints throughout, they weren't shoved in my face and saying "THIS IS WHAT HAPPENED!". Another thing I thought that was great about this book was the fact that you got to see parts of the twins lives before and after they were set free from their childhood prison, I especially liked the after as what we do in everyday was like learning a whole different language for the twins. If I could explain this book into 1 word it would have to be unforgettable, as even as I'm reading another book right now, I just can't seem to get Black Heart Blue out of my mind.Overall I thought this was a very powerful book and a great debut from Louisa, it's spine chilling and how Louisa managed to fit such a wonderful uplifting story into 266 pages I will never know.