In a flashback, Ofelia crosses the border into the U.S. and makes her way through the desert. A spray of bullets lands around her as an unseen assailant shoots at her. She hides behind a tree, but the shooter finds her. It’s Otto.
Otto brings Ofelia to his truck and interrogates her. Ofelia asks for a ride, but Otto says that “brown people” are not welcome at his home. She spits at him. He drives off.
Ofelia wanders through the desert and collapses, near death. She hallucinates and sees her father and Otto rescuing her. Walker discovers her in this state. He gives her water and brings her to the Black Hat.
Walker examines Ofelia, bathes her and offers her food.
Back in the present, Madison chases Ofelia as she tries to escape the ranch. She punches and interrogates her for answers.
The next day, ranchers load dead bodies onto a truck. Jake and Alicia tend to the sick, which includes Nick. Madison informs everyone that Ofelia poisoned the militia’s coffee.
Madison holds Ofelia at gunpoint and forces her to drive to the Black Hat. Ofelia insists that the powder was only supposed to make the militia sick so that Walker’s people could take over the ranch without bloodshed.
Madison brings Ofelia to Walker and demands to know what the poison was. He tells her that the poison was anthrax but says that Nick will survive if he’s able-bodied. He warns that she and her family will die if they don’t leave the ranch.
Strand scavenges for food. He looks out a window and sees a sight to brighten his spirits: the Abigail, run aground.
Strand wades into the water and boards the Abigail. Infected roam throughout the boat. Strand kills all Infected with a spear gun, knife and gun.
Madison tells Jake that the poison was anthrax and that those who don’t die will be too weak to resist an attack. Jake orders Troy to gather the remaining militia, but Troy is the only one left. Madison suggests they recruit the ranchers but Jake tells her she doesn’t lead the ranch.
Jake eventually agrees with Madison’s plan to fight and instructs Troy to arm anyone who isn’t sick. Alicia suggests they try to negotiate with Walker again. Jake points out that they have no leverage to broker a deal. Alicia hatches a plan.
Strand finds a bottle of Champagne on the Abigail. He goes to the upper deck, gets out a satellite phone and uncorks the bottle.
Nick convinces Jake to uncuff him from his cot, assuring Jake that he won’t turn. As Nick goes to look for Otto, Jake warns that Otto has another side to him and Nick will end up disappointed.
Nick watches Otto and several ranchers bury the dead in a mass grave.
Nick rips the floorboards of his adobe open.
Ofelia tells Walker that she cares about the Clark family and admonishes him for using anthrax without her knowledge. Walker maintains that she’s saving the lives of his people. They’re interrupted by a commotion outside.
The Nation rushes to extinguish a tipi fire started by Troy and a team of ranchers. As Troy’s team distracts Walker’s people, Madison and Alicia hitch the Black Hat reliquary to a truck and haul it off.
Nick digs a hole underneath the adobe floor. His shovel hits something hard.
Nick goes to Otto’s house and confronts him with a skull that he found under the adobe. Otto confesses that as the rivalry between the ranchers and the Black Hat escalated, the founding members of the ranch murdered three Black Hat men, including Walker’s uncle. He says the skull belongs to Walker’s father, who Otto killed when the man started to investigate his brother’s disappearance.
Madison and Alicia bring the reliquary back to the ranch. Walker follows with a host of soldiers.
Nick shows the skull to Madison and Alicia and relays the story he heard from Otto. He also reveals to Alicia that Troy killed the Trimbols. Alicia accuses Madison of being heartless for standing with Troy despite the murder of Alicia’s friend. Madison declares that she’s too busy keeping everyone alive to have time for feelings.
Strand makes contact with a Russian cosmonaut who’s stuck in space. The Russian tell Strand the rest of the world is Infected.
Madison meets with Walker and offers to return the relics in exchange for peace and ownership of the ranch. She gives him the skull of his father. He rejects her terms and gives the remains back.
Madison informs her group that Walker still wants the ranch and is giving them until sundown the following day to vacate.
Strand gathers supplies then douses the Abigail in alcohol and lights it on fire. He starts to make his way north.
In the bunkhouse, Madison reveals to Nick and Alicia why she’s never taken them to her hometown in Alabama. Madison shot her alcoholic father when she was a child because he beat her mother. She resolutely insists she would do it again if it meant protecting her family.
Madison goes to Otto’s house and tells him that Walker is willing to offer peace in exchange for Otto’s scalp. She puts her gun on his desk and urges him to kill himself. Otto refuses. Nick walks in and shoots Otto in the head. Madison quickly begins to put a plan into action.
Jake and Troy run to Otto’s house to find Otto dead. They remove Otto’s body from the house.
Madison walks up to Otto’s coffin in a barn.
Madison meets with Walker and places a backpack at his feet. He opens it and finds Otto’s head inside. He nods at Madison and walks away with the head.