I rate this just a 3 star mainly due to a poor finish but I have to say I quite enjoyed the ride up to that point.
No need to add a synopsis cause you can easily find that just a bit above. Not sure what to shelf it as though, I do need to work on my shelves here anyway but perhaps 'Thriller' is good enough.
My fave part of the book is actually the 'lost in the Peak' scenes. Read those at about 3am home alone and it was rather spooky.
I should add here that I really did not like her first novel at all so this one was a huge improvement.