A deadly plague threatens the town; racial tensions rise when the Irathients, who are immune to the virus, are quarantined.

Following the big storm, Nolan and Tommy find an American astronaut who has been in an induced sleep for the past several decades.

Kenya is kidnapped. Rafe learns that Luke was involved in some mysterious goings-on at the mines and orders Quentin to get to the bottom of it.

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.