Meh it was ok. If you've ever read mystery/thriller books you will probably find it predictable. I'm not say bad, just predictable.
The characters, the plot and the premise of how there could be a twist was a bit over the top entering into the realm of unbelievable, even for fiction. Which is probably how I guessed the broad strokes long before the end.
But it was a simple summer read so I guess the book did it's job.