I'm giving this book 4 stars based on the fact that it had a storyline that kept me intrigued and had me racing through the chapters to find out the ending. I liked the way the author interspersed past and present events so that you gradually put together the puzzle of why Cathy developed OCD and PTSD. There were a lot of details, especially toward the ending that bothered me or just didn't make sense. Overall, though, it was an enjoyable read (and just terrifying enough without giving me nightmares!).