Nolan and Irisa are mysteriously rescued from their underground confinement just in time to discover that enemy forces are marching on the town of Defiance, which has fallen on hard times following the collapse of the gulanite mines.

Amanda negotiates with the Omec, a new alien race, for the future of Defiance; and the Tarrs return to find much changed and their loyalties tested between the humans, the Omec, and the Votanis Collective. Meanwhile, Nolan and Irisa encounter a survivor of Votanis Collective atrocities that can aid their first strike against Gen. Rahm Tak's oncoming army.