Better than the last book. An eccentric billionaire head of a prestigious law firm hires Shawn and Gus to ferret out a murderer amongst his lawyers. He sends his team (Shawn and Gus, included undercover) to an isolated mountain-top and leaves them there. The team has to trek all the way down by themselves. Only one among them has the map and they're not telling. Shawn and Gus have to survive the perilous descent under the watchful eye of the murderer while making sure they're all not killed off one by one.
The book had an "And then there were none" feeling to it. Enjoyable.