The book has a complex set of characters and complex environment to absorb. It helps to have read previous books from the author such as 'The Descent' series. It has a gripping storyline that keeps you guessing throughout and to the end of the book. The main characters are also complex and one cannot help but be empathic with the circumstances they find themselves in. Belief systems are subtly questioned with respect to relationship and gender stereotypes. Makes you think... All in all well worth the read!