Fade is recovering from his horrific experiences with the "muties" and is struggling to re-form his relationship with Deuce despite his fear of being physically touched. Aguirre handles this aspect of the story sensitively and effectively, although I found that Fade maybe approached the problem more head-on and with more determination than I had been expecting at the end of the second book. He seemed very badly broken at the end of book 2 (Outpost) and almost too ready to address his desire to be with Deuce again at the beginning of book 3 even though this book takes off pretty immediately after the end of book 2 in terms of timeline.
One original aspect of this book is how much research Aguirre did into the ways in which battles might have been fought given the technologies these folks did (or didn't) have available to them. In her author's notes at the end she talks about how much research she did on civil war battle tactics and it shows in the writing. I suppose one slight downside of all the research is there is perhaps a smidgeon too much attention to battle strategy in this book potentially to the detriment of character development and story. There's a LOT of battle scenes and a LOT of tactics which are written very well and are very original in terms of placing them in a sci-fi/dystopian setting, but occasionally I felt "okay, enough already with the tactics, let's get on with the story". That's a minor point because the book held my interest from the first page to the last through some really melancholy moments and much dystopian despair and disaster. And Deuce remains determined to be "The Huntress", to raise her army to defeat the Horde, and to see her mission through to the end whatever life - and the world - throws in her way. She also continues her character arc towards growing up and deciding that there might be more to life than battles if she can just succeed with her mission. Highly recommend the whole trilogy and the final installment doesn't disappoint.