Where do I being , I was drawn in from the start. I swung from feeling empathy to disbelief as to lengths each character would go to, to achieve their end result. It was a game of cat & mouse just when I thought I knew where I was being taken , then wham another twist & turn took me off in another direction. 
This book is cleverly written to lead you down one path to then throw a curve ball in. I felt I was in the mind of the characters & could relate to the way they reacted given the circumstances. There are times in books I think " As if you'd do that " but I found the characters developed so as I could see why they had done " that" . Each clever twist & turn is intricately woven in to the plot so that when it explodes I though of course. 
I must admit John Marrs even had me feeling sorry for Laura at one point.