This was all geared up to be a solid 4 star rating, until the author didn't stick the landing in my opinion. I found the first half or so of the book extremely engaging and creepy, and kept reading because I really wanted to know where this was all leading! I had several thoughts and expectations of who I thought the killer(s) would end up being, but none of them were fulfilled. Many of the plot devices brought up early on, the white apparition in the woods, the bone ring, even Sara's evident walking of the town at night, were only brought up once and didn't seem to tie in much with the actual ending.
I also wasn't expecting fully fleshed out, three dimensional characters in a quick horror/thriller read, but I found a lot of the characters, particularly in the modern day setting, unrealistic and flat. Ruthie, in particular, made me scream at the book, horror movie style, with her poor decisions and lack of reaction in some places. I still don't understand Ruthie's reluctance to call the cops when her mom went missing, apart from plot convenience. Katherine's entire inclusion in the story felt unnecessary, as she was just a vehicle for the bone ring in the present day, and to be the one to call the next Sleeper.
So I docked it a star for my dissatisfaction with where the plot ended up and the ending. At 3 stars it's still an okay book, but I doubt I'll be recommending it to friends.