There's always a new threat.

A year after the Event, horrific memories of the vessels linger in Dean's mind as he tries to find his way forward in his new life. But now the heroes of Earth face a new threat that endangers the fragile remnant of humanity.

Two rebel hybrids have escaped from their segregated encampment. Dean and his team pursue them across the galaxy, racing to catch them before they reach an unseen enemy. This new threat is looming over Earth, their name spoken softly and fearfully by anyone who knows of them.

When a line is drawn, on whose side will Dean stand?