I liked this book well enough I suppose. I thought the protagonist, Michael, a teenage boy with a gift for unlocking nearly everything, was a well fleshed out character though I found him to be a little too much the "reluctant safecracker" for my tastes. Michael is unable to speak since a traumatic event which is not immediately explained. This made for some realistically uncomfortable situations in the story. The author obviously thought quite a bit about the problems that would arise for someone unable to speak. The plot was decent enough if the reader does not spend too much time thinking about it and the twist at the end was well played but ended, I think, with a bit of an unfortunate cop out..
I very much liked the portions of the book where Michael was opening the locks, these scenes were very well done and engaging. I also liked how the story came together as the two storylines alternated chapters. I would have preferred if the story had not opened with the protagonist explaining that he was in prison. I felt that this fact took away from the suspense of the ending.
All-in-All this was a worthy book, 3.5 stars but leaning towards 3.