|At a farmhouse, Bill Gibson is watching TV when the lights go out. He goes to the fuse box but discovers that the door wont' open. A door opens behind him and a pale woman comes in. The man recognizes her but says it's impossible for her to be there. He lunges at her and his blood flies everywhere.
Sam wakes up to discover Dean has pulled over and is eagerly looking for another case to take on. Sam figures that his brother is trying to keep occupied to avoid thinking about his time as a torturer in Hell. Dean ignores him and finds a report of a man killed in a locked room, in Stratton, Nebraska. They figure it's a ghost and head for the farmhouse. They go into the house, unaware that it's already been sold. Inside they find a sealed-over dumbwaiter and a decapitated doll's head, and high EMP readings. However, Dean is skeptical there's anything to be found.
The new family, the Carters, arrive with their furniture and the Winchesters realize the house has been sold. The daughter, Kate, isn't happy at the luck of reception and appeals to her uncle, Ted. The father, Brian, is less than thrilled when Ted agrees with Kate and his wife Susan tells him to take it easy. Kate notices Dean and Sam coming out of the house. The brothers claim to be county code enforcers there to inspect the problem. They say there's asbestos in the house, making it inhabitable. The brothers direct the family to a nearby home and Brian agrees to one night.
The brothers talk to the local housekeeper, Mrs. Curry, who confirms that Bill Gibson was brutally killed. She notes that Gibson kept to himself after his wife died in child birth and his daughter hung himself. She gives them photos of the family but doesn't know why the daughter hung herself. Mrs. Curry does remember that she heard rustling in the walls but never saw any rats. She also confirms that the dead women were cremated.
The Carters go back to the house and Ted confirms there isn't any asbestos. Kate thinks she's something in an upstairs window but dismisses it as imagination, and Susan tries to reassure her it'll be great there. Kate is skeptical.
That night, the son Danny is playing video games in his room when the closet door opens on its own and a baseball rolls out. He introduces himself and rolls the ball back in, and someone tosses it out.
Downstairs, Brian is in the kitchen and smells something dead in the closet. Susan wonders what they're doing there and Brian assures her they'll be happy there. Susan says she can't put the kids through another year like the one they just had.
Outside, the Winchester pull up and realize the family has moved back in. Meanwhile, Ted finds a message written in the wall in crayon, saying "Go." Brian thinks Danny is responsible and calls him down. Danny denies writing the message but his parents don't believe him. He claims the girl in the walls did it and wants them to go but Danny to stay. He warns that the girl will get mad if the grownups don't go. Danny says Andy would have believed them and Brian sends him up to his room.
Kate is trying to sleep that night and complains to the dog, Buster. It starts licking her hand from the floor but then the closet door opens and Buster comes out. Kate screams as she realizes something else was there and sees it duck into the closet. The family comes to investigate and Danny says it's the girl in the wall. Dean and Sam knock and come in, and Brian wonders if they're responsible. Dean warns them to get out but the lights go out and they hear Buster whimpering outside. They run outside with Brian and Ted and find a trail of blood leading to the car, and the words "Too late" written in blood on the side. The Winchesters try to convince them to leave and Brian agrees to go. However, they discover that something has flattened all the tires and stolen all their ghost-hunting equipment. Kate sees a girl in the woods but it disappears before anyone else can see it.
Dean and Sam get everyone inside and lay down a salt line. Brian is skeptical and prepares to leave but Sam convinces them to stay. He shows Kate the photos and she and Danny recognize the dead daughter Rebecca. Sam tells the Carters what they know and Ted wants to go out, but Dean threatens him into staying put. Sam goes up to the attic where Rebecca hung herself, but the others soon hear noises and the ghost of Rebecca enters the room. She approaches the salt line and then steps over it while drawing a knife. Dean gets the family out and tries to drive off what he now realizes is a human with a poker, and Sam arrives and drives it off with the beam of his flashlight.
The brothers go outside and assemble the family, while Sam reveals he found Rebecca's diary in the attic. They can't find Danny and Dean tells them to take refuge in the boarded-up shed. Brian tells Kate and Susan to go there while the Winchesters, Brian, and Ted, search up to split. Dean and Ted search inside and Dean finds a hidden panel in the wall. There's a passageway between the walls and the two men go inside. They find a tunnel leading down and Dean reluctantly goes down. He finds the dead dogs that the girl has been feeding on and a drawing of two stick figures. Above, Ted hears a noise, turns, and the girl stabs him through the head.
Outside, Sam and Brian find no sign of Danny and go back to the shed. Dean arrives and tells them that Ted is dead. Dean goes back outside while Sam reads Rebecca's diary. Brian tries to comfort Susan, who asks why bad things keep happening to them. Brian tells her that the same thing won't happen to Danny that happened to Andy. Brian goes outside and Dean asks him about Danny. Andy died in a car accident a year ago and Brian admits it's put a strain on his marriage. They moved there for a fresh start. Dean vows he'll get Danny back and Brian wonders why he cared. Sam interrupts and gets Dean inside. He explains that the girl is Rebecca's daughter, and Bill Gibson's daughter as well. Gibson locked the girl up until she finally escaped and killed her father. Dean figures where the girl is keeping Danny.
Danny wakes up in a basement area, bound and gagged. The girl approaches him and offers him a rat. She breaks its neck and starts eating it as Danny screams.
The brothers break through the wall over the dumbwaiter and Dean insists on going down to rescue Danny. As he goes down, Sam starts putting together a rope out of curtains. Meanwhile, the girl breaks into the shed.
In the basement, Dean finds their guns and locate Danny. He says "he" is coming back, and explains it's the girl's brother. The brother attacks Dean while Sam lowers the rope to Danny and pulls him up. Outside, the girl stabs through the walls of the shed as she tries to get at them.
Brian gets Danny out of the house while Dean tries to fend off the brother. Dean blinds him with the flashlight long enough to grab his gun and shoot the boy.
The girl busts in and attacks Susan… and is yanked backwards. Susan and Kate listen as they hear screaming noises outside. Brian comes in, holding a bloody knife. Dean and Sam come out and find the girl's corpse.
The next day, the Carters are packing while Sam and Dean load their equipment back into the Impala. Brian is giving them time to leave before he calls in the police, and thanks them for their help. Susan admits they're not okay but at least they're together. Down the road, the Winchesters pull over and Dean admits that he can sympathize with the Gibson children. Sam points out that they were barely human and Dean wasn't like them. Dean agrees, saying he was worse. He notes they were animals defending their territory, but he liked torturing souls in Hell. No matter how many people he saves now, he can't change what he did.