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.

Amanda’s mayoral campaign is threatened when Nolan is involved in an accident on the eve of the election, prompting the town to question Amanda’s decision to appoint him as Lawkeeper.

The citizens of Defiance prepare to cast their votes for mayor; Nolan’s past violently rears its head; Irisa must decide whether or not to embrace her destiny.

Nolan's desperate search for Irisa yields vital information which takes him south; back in Defiance, the Earth Republic has installed Mayor Pottinger, a charming, calculating and ambitious man who takes control.

Irisa returns to Defiance and is arrested; Mayor Pottinger offers Nolan her release in exchange for capturing those responsible for nearly killing him; Stahma plots to keep Datak behind bars.

Irisa's terrifying black-outs escalate, driving a wedge of secrecy between her and a worried Nolan. Meanwhile, the Tarr family business thrives under Stahma's self-appointed direction while an increasingly suspicious Datak remains in jail.

Nolan races to save Tommy’s life and stop Irisa before her growing forces can put their devastating plan into motion. Meanwhile back in town, Amanda learns the heart-breaking truth about her sister’s murder leading to a daring showdown between Amanda and Stahma.

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. Meanwhile, Datak, Stahma and Rafe run into deadly complications on their quest to reunite their family; and Alak comes to realize just how unstable her mother-in-law is during their journey through the woods.

T'evgin comes to Defiance seeking his daughter, who Nolan and Amanda offer to release in exchange for some gulanite; at the same time, Alak and Pilar head off alone to protect the baby; and Datak and Stahma are threatened into helping Gen. Tak's assault.

Nolan, Amanda and Irisa search for a way to stop Kindzi from transporting more Omec to Earth; Datak tries to escape from an Omec compound; Stahma asks for forgiveness.

Omec hunts Defiance citizens; Nolan, Amanda, and the others undertake a potential suicide mission to end the threat once and for all.