Sam and Dean drive up to a 24-hour diner and Dean sends a reluctant Sam in to get food. The Impala's radio flickers and then goes out, and Dean realizes that Sam has disappeared inside the diner. He runs in and finds a dead customer in a booth. Drawing his gun, Dean finds two dead cooks, their throats cut, but no sign of Sam. When he discovers sulphur on the door, he realizes that a demon is involved.
Sam wakes up on the ground in a seemingly abandoned ghost-town and is unable to get any reception on his phone.

Sam looks around and hears someone coming. He grabs a board and starts to attack the newcomer, and realizes that it's Andy, one of the other demon children. Andy explains that he was using a bong and smelled sulphur, and then woke up to find himself in the ghost town. They hear a woman screaming and go to the shed where she's been locked in. Sam breaks the lock and discovers that it's Ava Wilson, who runs into his arms. He explains that she's been missing for five months, but she doesn't remember any time passing for her. Sam doesn't mention that her fianc, Brady, is dead. Two more people, Jake Talley and Lily, find them. Sam explains that they're all 23 and they all recently discovered they have special abilities. Andy explains that he can now project images. Lily angrily tells them that anyone she touches, their hearts stops, and she's been confined to her home. She starts to walk off, but Sam says that they have to work together. He tells them that a demon brought them all together.

Dean finds Bobby, who informs him that there have been no demonic omens in the last month. Ash calls to say that he hasn't found anything either, but he did discover something else and he needs Dean to come to the roadhouse immediately. He insists that it's something big, and that it will help find Sam. Dean and Bobby leave in the Impala for the roadhouse.
None of the others believe in Sam's story about a demon, and Jake goes off on his own. As he walks down the street, he sees a young girl looking at him from a door. He enters the abandoned schoolhouse and looks in horror as the words "I will not kill" appear repeatedly on the chalkboard. The girl appears, grows claws, and moves in for the kill, but Sam arrives in time to use an iron poker and dissipate it. He sees an engraved bell and realizes they're in Cold Oaks, South Dakota, one of the most haunted towns in America. Lily is ready to walk away, but Sam warns that there are miles of woods and they have no idea what's going on. She insists that there's no "we," and she accidentally killed her girlfriend. Sam points out that they've all lost someone, and their best bet is to stick together. They start searching for silver, salt, and iron to use as weapons. However, Lily soon slips away and takes off into the woods.

Dean and Bobby arrive at the roadhouse and discover that it's been burnt to the ground. Searching, they find dead hunters, including Ash, but no sign of Ellen.
As Lily makes her way through the woods, she hears children laughing and sees branches moving around her.
As Sam and Ava search, he finds a knife and notices that Ava looks ill. She says that she's just feeling dizzy from hunger, but insists that she's fine. Andy and Jake call them over to a building where they've found two bags of salt. Sam realizes that Lily is gone, and they hear children's laughter. Going outside, they find Lily hung by the neck from a windmill. Ava and Andy want to leave, but Jake and Sam realize that Lily tried and failed, and they'll have to gear up against the next attack. Andy gets an idea and asks for something that Dean has touched.

Dean and Bobby are trying to figure out where to go next when Dean grabs at his head in pain. He sees the Cold Oaks bell and Sam, and tells Bobby about the engraving on the bell. Bobby recognizes it and realizes where Sam is.
Jake uses his bare hands to break apart a wheel for its iron spokes, and explains to Sam that he started displaying super-strength in Afghanistan where he served. The soldier thanks Sam for keeping everyone calm despite how freaked out he is, and Sam explains that he's just doing what Dean has always done for him. However, he warns Jake that it's going to get bad.
The four survivors take refuge in a building and Sam puts down salt lines. Ava asks how he's doing and wonders what they did to deserve what happened to them. When she mentions Brady again, Sam flinches and she realizes that he knows something. He finally tells her that the demon killed Brady and holds her as she cries.

The night passes and Sam dozes off. He wakes up and sees the Yellow-Eyed Demon, but none of the others can see it. Sam realizes that he's dreaming, and the demon invites him out for a walk. He explains that it wants Sam to win, and that he only needs one soldier for the coming war. The Yellow-Eyed Demon has gathered an army, and wants a leader. He considers Sam his favorite, and killed Jessica to force Sam out onto the road to hone his skills. Mary's death was unintentional, because she came in on them. The Yellow-Eyed Demon then creates a vision to show Sam the night that Mary died. The demon fed baby Sam some of its blood. Mary came back, recognized the Yellow-Eyed Demon, and it killed her.

Sam wakes up and Jake informs him that Ava is missing. They go outside and split up to search, unaware that Ava is watching them from the shadows. Andy stays behind, inside of the salt lines, and finds Ava breaking the line on the window. She clutches at her head and demon smoke flows through the gap, solidifies, and kills Andy while Ava looks on, smiling. She then screams in fake horror. Sam hears her and comes running, and she claims she found Andy dead. However, Sam realizes that she broke the salt line and that her earlier illness occurred the same time that Lily died. Ava finally admits that she was fully aware of what was happening the last five months, and eliminated other batches of children as they were sent there. She boasts that she enjoyed it, and that Sam would enjoy it if he'd open himself up to his power. Ava summons another demon and it starts to enter the room, but Jake breaks her neck, sending it away.

Dean and Bobby drive up to the border of Cold Oak and discover that the road is blocked. They arm up and go on.
Sam figures that they can leave now that Ava isn't sending demons after them. However, Jake says that the Yellow-Eyed Demon talked to him in a vision, and if they don't play along, it will kill both of them. He figures that once he kills Sam, he can get close to their enemy and then destroy him. Sam asks him to trust him, takes out the knife he found earlier, and puts it on the ground. Jake picks it up and then knocks Sam back. He comes at Sam, who manages to fight back and knock him out. Sam picks up the metal rod and knocks Jake out, and then prepares to deliver a final blow. He stops and throws it away, and hears Dean yelling for him. He walks over to Dean and Bobby, who can only watch as Jake grabs the knife and stabs Sam in the back. Bobby goes after Jake while Dean holds his brother and tries to assure him that he'll be okay. Sam dies as Dean screams his brother's name.