I'm technically halfway through this book and past first major battle of the war. If you're an avid reader you know what I'm talking about, if not then you need to catch up! At the moment I'm trying to set the stage for the next book, which will cover The Purge, mentioned in books 1 and 2. No, no, not the dumb movie The Purge. Something wildly different and way better.
So far, this book has been mostly action and should stay that way to the end. Given that this is the beginning of a war that's the whole series has been building up to, there's not much need to work additional plot in, other than to foreshadow what's to come.