Sci-fi authors do love their tropes, especially when they write a series focused on the discovery of an overwhelming alien threat, which has been done many times before. Invariably, after it becomes obvious that humanity is not prepared and faces a real possibility of being wiped out, the story turns inward and the human infighting commences. This is also where I sigh as the story goes on a tangent from the storyline that has my attention; however, much like he did in book one, Joshua Dalzelle embraces this typical trope and finds a way to deliver a compelling story anyway. This means that Call to Arms is more about human interactions than it is about the alien threat looming in the distance, but it is still worthy of your attention and it does set things up nicely for the series finale.
Call to Arms - a solid middle book in the Black Fleet Trilogy