Three months after the shock of Henry’s suicide, it’s winter. An old man comes back from a hunting trip to find an unexpected guest with his wife: Joel. Holding them at gunpoint, he asks if they have news of Tommy. Nothing. He forces the man to show where they are on a map, insisting that his answer better match his wife’s. Lucky for the old man, he points to the same place. Ellie’s question about Fireflies is met with laughter. The old man warns Joel about the dangers across the river, infected and human.
Ellie is undaunted. She steals a rabbit as they leave the cabin. But Joel’s spooked by the idea of his brother being gone. He has PTSD flashbacks, worrying Ellie. Joel only comes back to himself when Ellie points out she needs him to survive.
They walk until dark, making camp for the night. Joel drinks from his trusty hip flask, letting Ellie have one sip. She asks what they’ll do after the Fireflies use her blood to make a cure. Joel checks her use of “we.” Undeterred, Ellie asks where he would go if he could do anything. And Joel admits he’d like to raise sheep on a ranch – because they’re quiet and do what they’re told.
Ellie rolls her eyes and shares a deep love of space, fangirling over Sally Ride. Then Ellie reveals how she’d tried to save Sam, and asks Joel if the cure will work. He reassures Ellie that Marlene knew what she was talking about.
Despite promising to take both watches, Joel falls asleep. He wakes up to find Ellie keeping watch with the rifle, which he takes back. They cross the river, Ellie trying to learn how to whistle, and find a dam. Joel’s trying to explain how it works when they’re surrounded by a group of riders on horseback, each one armed.
Joel has no choice but to drop his gun. They send a dog trained to sniff out infection, and Joel freezes, lost in a memory of Sarah. But the dog only wants to play.
When questioned, Joel admits that he’s looking for Tommy. And the riders take him and Ellie to a town barricaded with high wooden walls: Jackson. Inside, children build snowmen, shops sell goods, and a Christmas tree stands in the middle of the town square. And Tommy’s there, building with a construction crew. He and Joel hug it out while Ellie watches.
They stuff their faces in the dining hall with Tommy and one of the riders – Maria. In true Ellie style, her appreciation is sweary. And in true Dad style, Joel reminds Ellie to mind her manners. Ellie points out that the girl (young Dina!!!!) staring at them isn’t minding hers. She argues with Maria, wanting her gun back.
Joel asks for a moment with family, and Tommy explains that Maria is family because they’re married. Ellie congratulates them and makes Joel say it too. Then Maria gives them a tour of Jackson, explaining how the walls and a bad reputation keep the raiders away. They have electricity, crops, and livestock – everything collectively shared. Tommy rejects the label of communism, but Maria embraces it.
Ellie pats a foal named Shimmer while Joel leaves to talk with Tommy, promising Ellie she’ll be fine. Jackson has a bar, complete with ice. Tommy thanks Joel for looking after him. When asked about Tess, Joel lies and says she’s fine. He spins a yarn about Ellie too, pretending she’s the daughter of a Firefly official. Tommy directs him to a Firefly base at the University of Eastern Colorado, warning about raiders.
Joel invites Tommy along for the trip, but he’s committed to Jackson. Old resentments bubble up and the brothers argue about Tommy’s radio silence, and the people they killed to survive after the outbreak. Tommy refuses to go with Joel because Maria’s pregnant. Joel, triggered by the news, fails to congratulate him.
Tommy loses his temper and Joel storms off, having a panic attack outside. He watches a young woman who looks just like Sarah might have collect her daughter.
Ellie showers, acquiring a diva cup and a familiar outfit. She finds a memorial to Kevin and Sarah in Tommy and Maria’s house. Maria cuts Ellie’s hair, revealing that Sarah was Joel’s daughter. She warns Ellie there are other things she may not know about Joel. But Ellie is fierce in her defense, pointing out that Joel only kills people who deserve it now and Tommy is a murderer too.
Maria takes Ellie to film night. And Joel’s attempt to repair his boots is interrupted by Tommy bringing a him new pair as a peace offering. The brothers reconcile, and Joel shares the real purpose behind their journey: Ellie’s immunity. Tommy is shocked, asking for the whole story. Joel opens up about his trauma. In tears, he begs Tommy to take Ellie to the Fireflies, because he’s terrified of failing another girl in his care. Joel argues that a cure will make a better world for Tommy’s child, and he agrees.
Joel goes to break the news to Ellie, who’s reading a teen girl’s diary from before the outbreak. But she overheard the conversation and asks Joel if he cares about her. Joel tries to persuade Ellie she’ll be safer with his younger brother. She confronts him about Sarah, making a passionate speech about how everyone she has ever cared about has either died or left – except for Joel. And he’s brutal in retaliation, saying they’re splitting up at dawn. Alone in his room, Joel cries as he remembers Sarah.
In the morning Ellie has lost her usual spark. She’s packed and dressed, waiting for Tommy. They go to the stables. And find Joel lingering. He says Ellie deserves a choice, and that he still believes Tommy is the better option. But before he’s even finished speaking Ellie chooses Joel. Tommy gives Joel directions, a hug, and the offer of a home when they’re done.
Joel and Ellie ride away from Jackson. In Dad mode once more, he teaches Ellie how to shoot the rifle. And Joel softens, telling Ellie about his life pre-outbreak and explaining the rules of football. They ride through the ghost town of a campus,
Ellie amazed by young adults whose only real responsibility was studying. Joel informs her there was partying too, and admits he wanted to be a singer. And Ellie extracts a promise that he’ll sing for her when she’s saved the world.
They spot monkeys loose on campus, left over from the science lab – and a graffiti Firefly logo. But there are no guards. The building’s empty. They find an old packing list – evidence the Fireflies shipped out. A distant echo makes Ellie wonder if any Fireflies stuck around. But it’s just more monkeys. And a map with St Mary’s Hospital marked in Salt Lake City.
This victory doesn’t last. Raiders arrive as Joel and Ellie leave. They sneak out of the science lab, and are ambushed by a lone raider. Joel snaps his neck. But not before getting stabbed. Ellie helps him back onto the horse, shooting at the other raiders. The raiders can’t keep up, and they escape. But Joel passes out and falls from the horse. Ellie panics, alone and afraid.
