Thanks to Lawson Sawyer and the ancient mech known as the Archetype, the threat of the alien Ravennox has been averted—for now.

The Ravennox are still out there. But thanks to Darius Spann and the Superba, Lawson and the other forces of the newly-restored Cygnus Realm face another, far more immediate threat. Spann and his Superba allies still hold sway over a huge swath of human territory, declaring it all Imperial space. Humanity is split, the Realm on one side and the Empire on the other, both claiming to be led by the Messenger. With neither able to land a decisive blow to knock out the other, a cold war now simmers between these two competing visions for the future.

Philosophies clash. Border skirmishes flare and fade. Schemes and intrigues abound. People die.

Spann is determined to break the stalemate and reunite humanity under the iron grip of Superba rule, with him as its leader. To do that, he will travel into the spinward reaches of the Milky Way's Sagittarius Arm, seeking new and powerful allies. First, though, he resolves to recover some of the ancient war machines of the enigmatic Unseen, powerful mechs, each nearly as mighty as the Archetype itself—or die trying.

Meanwhile, to Lawson and the Cygnus Realm, it is only too clear that the Ravennox threat is far from ended, and they desperately need to learn more about these mysterious aliens. But they must also counter Spann's efforts to recruit new alien allies of his own, who themselves could pose as profound a threat to a divided humanity as the Ravennox. They must mount their own spinward expedition.

As the two factions jockey for power and prepare to launch themselves into the vast galactic unknown, one thing is starkly clear: Only one of them can prevail.

Will humanity be governed as envisioned by the First Messenger and the Unseen, with egalitarian wisdom, or will it be ruled by ambitious powermongers who see themselves as humankind's better future?

The survival of humanity itself in the face of implacable alien threats hinges on the answer to this, the most important question ever posed.