Initial reaction: Omg. Wow.I haven't been this enthralled with a book in ages. I stayed up most of the night because I HAD to know what happened. Here are some thoughts!This book was written beautifully; it was so picturesque that I had the most captivating images in my head throughout the entire novel. Haden's world is the most eerie but somehow still stunningly beautiful place to read about. The "beings" that existed in it were so amazingly thought up (especially the three women Mara had dismembered and put back together incorrectly). Hayes embodied a version of hell that was so interesting to read! My favourite parts of the novel were all taking place in Under. I loved Mara (even though she is the epitome of evil) and her shameless pleasure in the destruction of others. She was such a rounded character. Reading about her, I could picture her perfectly. Just the same way I could picture Haden in his top hat; the star of a waltzing troupe in hell.Donny and Ame were cute characters. They were all so different, creating a great group of people for Theia to bounce off. However, Varnie was by far my favourite "friend" character. The fact that he is a surfer dude alias fortune telling cross-dresser was just way too great. I hope him and Ame get together in the following books!One thing that got to me was that I was slightly convinced that Theia's mother was going to end up being some sort of paranormal creature herself -- although there are more books coming, so it is still possible! There is just too much mystery surrounding her mother to not explore those possibilities.Lastly, this book got steamy! When Haden touched other girls and gave Theia tingling sensations, I was fanning myself! For a YA, the sexual tension of this book was fantastic! When they finally do start having physical contact, it just starts getting better! I loved their desire for one another. I find YA is very careful with the topic of desire and sexual lust but this novel handled it honestly and accurately. All in all, I loved this book and will recommend it to anyone who loves a phenomenally constructed underworld and a daring, tension-building love story. I am anxiously awaiting the next one!