3-1/2. A little slow to start but the suspense ratchets up and it becomes had to put down at the end. Lots of interior monologue for main protagonist (which makes some sense considering to situation he is in) and very descriptive with the olfactory senses, but less so with visuals. Back stories become a bit hard to believe but make a good if slightly contrived story. Twists are a little obvious but enjoyable.