Synopsis
Hunter Rufus Turner calls in Bobby, Sam, and Dean to deal with a demon infestation in his town, but they soon discover the truth is much more horrifying. Meanwhile, Castiel goes to seek the only entity that can defeat Lucifer.
Full Recap
Bobby is recuperating in the hospital but is deeply depressed and Sam warns Dean that Bobby might not bounce back these days. Dean shows Sam an x-ray he had taken which shows the sigil carved on his ribs. Castiel calls Sam on his cell phone and learns where he is and the hangs up. Castiel arrives and explains that they're hidden from all angels, including himself. Bobby demands that Castiel heal him but Castiel says that he can't because he's cut off from much of Heaven's power.

Castiel then tells Dean and Sam that their plan to kill Lucifer can't be done, but he believes there is another being strong enough to take on Lucifer and stop the Apocalypse: God. He plans to find God. Dean doesn't believe that God is alive, or if he is then he's not involved. Castiel reminds Dean that he and Sam failed and tells him to keep his opinions to himself. The angel explains that he came for an amulet that burns hot in God's presence and will help him find the Supreme Being. Castiel reveals that the amulet is the one that Dean wears. Dean hands it over and tells him not to lose it.

River Pass, Colorado

Former hunter Rufus Turner returns fire at an unseen opponent and moves a wounded townsperson to cover. He then calls Bobby and says the whole town is infested with demons. The connection cuts out as Rufus fires at two approaching figures.

Dean and Sam drive to River Pass but discover the bridge on the only road into town is out. They hike into town and find devastation and destruction, but no sign of the townspeople. They finally locate a survivor: Ellen Harvelle. She sprays them with holy water to make sure they're not demons and then walks past them. They follow her to a church sealed with devil's traps and then embraces Dean. Then she slaps him and wants to know why they didn't call her. She figures that it's the end times and warns that almost everyone in town is dead or demon possessed. She introduces them to the last few survivors. Ellen tells the brothers that Rufus was in town hunting omens and the demons suddenly attacked. Jo was with Ellen: the two have been hunting for a while. Mother and daughter got separated and Ellen was looking for her when the Winchesters arrive. She warns that the last time she tried to get out of town, she lost several of the remaining humans. Sam figures they should arm everyone with salt and Dean suggests they go to the hunting store to get weapons. As they leave, Dean suggests that he go alone and Sam help train the civilians. Sam realizes that Dean doesn't want him around demons. When Dean denies it, Sam insists on going.

Outside, Dean initially refuses to separate but they finally go in different directions to get salt and guns. At the general store, Sam loads up on Salt when he sees two men come in. Sam goes for his gun and the men come at him. He tries to exorcise one of them but it doesn't work. He manages to stab the first attacker with the demon-killing knife and then takes out the other one. However, Sam sees blood on the floor and realizes something is wrong. Dean comes in and finds him standing over the two dead men.

The brothers get back to the church and start training the townsfolk. One of them, Austin, is a soldier and he believes Dean is as well. Dean goes over to Sam, who regrets that he had to slit two teenagers' throats. He wishes he could save people like he used to, but Dean points out he had to drink demon blood. Before Sam can respond, Ellen tells them she's going to find Jo. Sam wants to go but Dean asks to talk to him in private. Dean insists on going again and Sam figures that his brother still doesn't trust him. When Dean wonders if he's learned his lesson, Sam shoves him back and then manages to get a grip on his temper.

Sam and Ellen search the town and she asks about what's up between him and Dean. Sam says that it's the stress of the job and admits that he's surprised Ellen lets Jo hunt. Ellen admits that she doesn't think Jo can handle it, but figures she'll do it anyway. They spot smoke from a chimney and approach the house it's coming from. They spot a black-eyed demon-possessed man in the window and Sam wonders what they're burning. Two demon-possessed humans attack them: one is Jo. Ellen tells the demon not to hurt her, while Jo calls Ellen a black-eyed bitch and demands that she give her mother back. A third demon knocks out Sam and Ellen runs away. Sam looks up to discover that Rufus is the attacker.

Sam wakes up inside the house, tied up. Rufus and Jo, their eyes black, say he's stuck right where they want him. Jo sprays him with holy water and then Rufus pours salt in his mouth while chanting an exorcism.

Ellen gets back to the church and tells Dean that Sam didn't make it. Dean starts to go after his brother but then stops and realizes they need a plan.

Rufus and Jo, who see Sam with black demon eyes, wonder why the salt and holy water aren't working. Meanwhile, Sam notices one of the townsfolk from the church, Roger, hiding in the doorway, and sees a demon's trap on the ceiling above him.

Jo tells Dean that they have to get the demon out of her daughter without hurting her. Ellen wonders why Jo called her a black-eyed bitch, as well as how the demons got past her daughter's anti-possession amulet. Dean admits he'd rather call Bobby for help but that's not an option. Ellen explains that Rufus was checking out water. The pastor says that the river suddenly became polluted and Austin says that there a large shooting star passed over the town the same day. Dean checks out a Bible and reads from Revelation 8:10, which talks of the Apocalypse and Wormwood falling from the sky. The pastor explains that Wormwood signifies the coming of the Four Horsemen, and Dean remembers seeing a red car in the street, symbolizing War's red horse. He figures that War is responsible, turning them all against each other.

Once Rufus and Jo leave, "Roger" comes in and introduces himself as War. He's waiting to hook up with his three siblings and Sam realizes what he's been doing. He threatens to kill War, but the Horseman points out that Sam can't stop thinking of killing since he saw the blood on the knife. War says that Sam wants to be strong, stronger than everybody. He then twists his ring and blood drips from his head. Finally he kicks over the chair and screams in pain. Rufus and Jo come in and Roger says that Sam did it. Rufus hits him and ignores what he's saying.

Roger returns to the church and says that the demons plan to pick them off one by one. Dean is suspicious but Roger insists that they have to wipe out the others. When Dean balks, War twists his ring and the townspeople see Dean and Ellen as demons. Austin and the pastor grab guns and Dean and Ellen run out. Austin loads up the shotguns with real shot and War goes to get some knives.

Rufus rigs the window of the house with a pipe bomb. Jo protests, noting that one of them is in her mother. Rufus says he'll do what he can and Ellen will be okay, but Jo doesn't believe it. However, she stills give him another bomb.

Austin's group leaves the church, hunting for demons.

One of the bombs at the house goes off and Rufus and Jo go to investigate. Dean pulls Rufus out the window while Ellen grabs Jo and tries to get through to her. Dean tries the same with Rufus, reminding him of the omens. Rufus fights back and goes for his gun, but Dean finally manages to get through to him and Rufus shakes off the hallucination.

Austin's group moves toward the house. Ellen gets through to Jo, and Dean figures they have to find War because everyone kills each other. Dean goes to free Sam, who explains that War used his ring to induce the hallucinations. Rufus, Ellen, and Jo try to hold off the townspeople and keep their side from shooting the other. The pastor goes down and Ellen goes to help him. Austin throws her to the ground and shoots her, only to discover that he's out of bullets. He grabs a knife and tries to stab her.

War goes to his Mustang but Dean and Sam grab him. Sam uses the demon-killing knife to cut off his finger. Austin and the others snap out of their hallucinations just in time. War disappears as Dean picks up the ring.

Later, Sam and Dean contemplate the ring and wonder what to do with it. Sam insists on telling Dean that he's realized that he doesn't trust himself any more than Dean does. He tells himself that his intentions are good but underneath, he just misses the feeling of power. Sam worries about whatever is inside of him and says he needs to step back because he's dangerous. He figures it's best if they go their separate ways. Dean agrees with him, saying he's more worried about Sam then doing the job right. As Sam starts to leave, Dean offers him the Impala but Sam refuses. They wish each other well and Sam catches a ride out of town.