The sixth episode of Marshals picks up a year ago, as Kayce and Tate pay their respects to Monica. This hits them both hard, and as Kayce ponders this, we cut back to the present. There's still no word on Hayley, and Tate is frustrated by the lack of activity. Of course, he's still torn up over Monica, and given it's the anniversary of her death, he's struggling. He blames himself for not getting involved and helping Hayley when he had the chance.
Kayce vents his anger on the shooting range while Andrea hits the bag. They're all sitting around twiddling their thumbs until Belle rushes in with news. It turns out that Bludsoe visited a mechanic shop shortly before they killed him. He called the mechanic, Eli Craig, and that could be a lead to follow.
Miles and Calvin show up to see Chairman Rainwater, who's joined by Ava's mum and breaking the bad news about Ava. It seems like Craig is just another link in the trafficking chain, but in total, there have been 43 girls that have gone missing - and those are just the ones that have been reported. Footage from the mechanic shop shows suspicious activity with a white truck, and someone driving it seems to be wearing an Iron Sentinels vest.
The Iron Sentinels are essentially "mafia on wheels" and they're big opportunists. They have a clubhouse out by Cowan that could be a good lead over where the girls are being kept. Kayce wastes little time showing up and causing a huge explosion, lighting the bikes on fire and drawing the bikers out of the clubhouse. Every single one of them head out (which is lucky!) and that leaves Miles and Andrea enough time to look around and try to find clues. They rip a cell phone left on the table and notice that the girls could well be at an Iron Sentinels rally at the Milk River valley area. Furthermore, a weird message says "Brimstone's bringing the entertainment", which could be a clue. Is it drugs? The girls? An Elton John tribute act? We'll have to wait and find out.
Calvin reluctantly agrees to proceed with Belle's plan, as they are left without the support of local law enforcement. However, Belle surprises them with a revelation: she once ran an undercover operation against the Iron Sentinels, specifically targeting a member of their St. Louis chapter named Squirrel. She proposes to re-establish her undercover identity and gain access to the rally, where she can gather information without resorting to violence.
The team decides to use the methamphetamine they obtained a few months ago as a means of infiltration. They agree to play defense in case things go south, but Calvin is concerned about Belle's safety and confronts her, warning her that her husband won't be pleased with her putting herself in harm's way.
Belle, undeterred, changes her attire and heads to the rally. Despite no sign of the girls yet, she approaches her contact, Squirrel. She quickly gains his trust and is introduced to Brimstone, the leader of the Iron Sentinels. Belle plays her part well and convinces Brimstone to do business with her. When Brimstone leaves, a problem arises: one of the bikers seems to recognize Belle, although he calls her "Turek," which ties into the reckless gambling Belle was involved in earlier in the season.
The rest of the team decides to move in and backs up Belle. She takes out the biker with a gun, and Kayce helps subdue him and Squirrel. Squirrel informs them that there's a box truck at the back of the rally holding the cargo. Just as they get this intel, chaos erupts. The group quickly disposes of the bikers and finds the girls inside the truck, packed in barrels.
With the girls found and the bikers taken down, Kayce returns to the ranch and shares the good news with Tate. However, there are parental issues back at base for Calvin, as he wants to try and reconnect with Maddie but knows it's an uphill battle at this point.
Tate and Kayce head off to pay their respects to Monica and Ava, joined by the team and most of those from the rez. Kayce also hands over the necklace to Tate, reminding him that he's been holding onto it since her passing.
