Mary seriously considers giving up her operations for good.

Ben follows Mary to her childhood home where he learns about her past. Grady approaches Mary with an offer. Des becomes a victim of police misconduct.

An old war buddy catches up with Nolan at the same time a Castithan criminal with a history of violence enters the picture.

Rafe & Nolan search underground St. Louis while looking for an escaped convict. Meanwhile, a violent Castithan tradition causes clashes amongst the residents of Defiance.

Nolan and Irisa arrive in Defiance, where the town is soon divided over the death of Luke McCawley. But a bigger threat forces everyone together: An attack by the Volge.