Irisa clearly has a problem with torture, unlike some Castithans we know (read: all of them). They're stringing up citizen Elah Bandik by his wrists and ankles in order to cleanse his soul of cowardice. When Nolan sees the community placing rocks in a basket that makes the ropes pull tighter, he tries to shut it down, but Bandik pleads to let it go on. When Mayor Amanda shows up, Datak - the most torture-y of them all - challenges her to defy the precedent her forerunner laid down. It seems like, after leading a successful defense against the Volge, Amanda would be less afraid of living up to expectations, but she bows under pressure and orders Nolan to stand down. She tells him in private of an incident with Irathients refusing to vaccinate their children years ago. The conflict between the city and the Irathients grew bloody, therefore Amanda won't stand in the way of cultural beliefs, no matter how gruesome they seem to humans.
More pressing things await: Mr. Birch, who is associated with Mayor Nicky jolted saboteur Ben Darris out of his coma. Ben stole an explosive called gulanite and escaped down the mines to Old St. Louis. McCawley informs Nolan and Mayor Amanda that he has 20 kilos of the stuff, thereby informing the audience that the U.S. finally switched to the metric system. But seriously, Ben's underground with more explosive than he knows what to do with, and why is he underground where it won't do any good? He used some of the gulanite to blow up the tunnel behind him, so in order to catch and question him, Rafe will have to lead a team through the other tunnels, nicknamed the Rat's Nest. Nolan makes sure Rafe doesn't kill Ben, and after the two St. Louis natives bond over their favorite pre-Votan dining spots and a dog food jingle (turns out Rafe's family made the stuff pre-apocalypse), it becomes clear that Ben is headed for the nuclear plant that went up during the war.
They track the gulanite to Ben and the plant just as he's about to set of the bomb. Rafe gets in a lucky shot and wounds Ben, and Nolan disables the bomb. He has to talk Rafe down AGAIN in order to keep Ben alive, and even then, Ben trash talks Rafe, saying Luke was in cahoots with him just to get some cash and get away from Rafe. It's like he WANTS to get shot! Actually, he did, ‘cause the minute Rafe lowers his weapon, Ben grabs it and shoots himself in the stomach, whispering, Citizen Kane-style, "Tell Amanda I'm sorry." Thanks for the info, loser! I guess he was just trying to save his family, whom Nicky and Mr. Birch have threatened.
Speaking of family, Alak has stumbled into his parents' bath time together, which is a little gross, but maybe it's a Castithan thing. He's upset because Christie might call off the wedding to appease her father, but doesn't seem at all upset by the naked hug Stahma gives him when she says she'll take care of everything. Datak was just ranting about how the humans need to stay out of the Elah Bandik situation while Stahma tried to get him to let go of the traditions that would've kept him in the lowest liro, or caste, back home. He responded by saying that he likes the caste system now that he gets to step on people instead of the other way around, which makes sense if you're a psycho. When he tells Alak that he'd like to kill Rafe, Stahma smoothes the situation over as best she can.
Stahma goes to the cafe where Christie works and tells her the story of how she met Datak. He found his way onto the emigration ship by collecting a gambling bet and aggressively courted her, despite her being betrothed to a man (chosen by her parents) from the highest liro. The betrothed challenged Datak to a duel, but on his way there, he "accidentally" got flushed out of an airlock. Christie's suspicions are piqued, but she gets the moral if not the morality of the story: sometimes you know who you're supposed to be with better than your parents do.
Nolan, Rafe and Amanda return to the surface with the dead Ben just as Datak enters the Lawkeeper's office demanding the release of Elah Bandik. After Irisa climbed the rack and cut the man down, Castithans began throwing rocks at her. Deputy Tommy showed up and saved her, but Irisa's pissed at him for that, too. Tommy brilliantly arrested Bandik for loitering in order to circumvent the "turn a blind eye" policy, but Datak and his goons won't have it. Just as a gunfight is about to break out, Amanda shows up and tells him that she's putting an end to that barbaric ceremony. With murder in his eyes, Datak kisses her hand and offers peace. They can speak of the subject after the town's evening service for those fallen in battle.
What he really means is, he'll kill Bandik in private and leave the body at the door of the Lawkeeper. Castithan subtext is so tricky.
But human subtext can also be tricky, because when Nicky came to visit Defiance to get her things, she told Amanda she was going to miss her. Amanda thought it was an overly-sentimental way of saying how much she meant to her, but Nicky actually meant "I'm going to miss you AFTER I KILL YOU," which is totally not what most humans would infer from those words and an affectionate pat on the cheek.