Humankind is under the gravest threat in its history. The enemy Naxli keep advancing, taking humans prisoner and destroying human worlds. But this isn’t the Naxli’s first rodeo, and humanity is not alone. Other races have suffered at the hands of the enemy, and they’ve proposed that humanity join them and present a united front to defeat the Naxli once and for all. The Congress of Humanity deploys the First Human Expeditionary Brigade to join with the alien military to take the fight to the Naxli. But with seventeen known “allies,” all with different goals and perspectives, how can they form a unified, integrated fighting force? It’s been hard enough for humans to cooperate throughout history, and now the problem has just logarithmically increased. Still, a mission is a mission, and Gunnery Sergeant Reverent Pelletier, Perseus Union Marine Corps, is going to do what he can to create an effective fighting unit, even if he has to beat in some alien heads to get it done.