This is the second book in the series, I would recommend reading the first (Birdman) before starting this one as it does refer back to the story quite a bit even though the crime is unrelated.
If you liked the first book, you will very probably enjoy this one as well. Mo Hayder delivers a very thrilling book once again.
For me this one was a lot harder to read though. It is not for the squeamish, and it does involve children. Though luckily the scenes involving children is not as vividly described as most of the book!
I don't 'read' audiobooks a lot, but this one was well done, it was a Norwegian translation, and both the translator and the narrator has done a great job in my opinion.
I would have reated it a 4 if not for the fact that it made me very uncomfortable in places (which I expect is on purpose).
Well worth the read but not for the more sensitive!