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

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

Interesting relationships develop when the residents of Defiance are forced to stay indoors as a threatening Razor Rain storm approaches. Meanwhile, visions lead Irisa to the Spirit Riders and Sukar, who has fallen under the influence of a strange and mysterious force.

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