Each of the books of the forgotten colony books so far has had a dark tone to them. In this book, the author takes it to the next level in becoming darker.
If you like a character, be prepared to say good-bye. If the character had a little bit of a moral spine, say good-bye. The author has no problem killing off characters left or right. I believe that he is trying to make sure that the reader understands the frailty of human life. One would have to come to the conclusion that the author seems to enjoy the scenes of killing off characters people want to see survive since he seems to believe that anyone that could half-way be considered decent or moral would die during the apocalypse. The only characters the author seems to want to keep are despicable characters who will not even die when a lesser injury kills someone else.
By the time you reach the end: one of the original characters is badly injured, one is no longer in control of their own body, and one you would like to see die is still coming out on top.
Another reason for the low score for this book is that the re-introduction of the heroine(?)(I think this is the author's hero since she overcomes all obstacles even death) is very formulaic. Sargeant Card has to fight someone who is trying to get entry? Hmmm, who could that be? Oh, it's just the author's heroine coming back into the story to make sure that everyone else dies.
Supposedly there is one last book in the series and I will wait until that one is out and read before I pick up any of this author's other books.