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

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.

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