|Jenny and her two children have just moved into a house in Lawrence, Kansas. The eldest child, Sari, belives that there are monsters in closet, screaming out in the night after she sees a flaming ghost in there.In a motel, Sam awakens from a nightmare and realises that the dream was of their old house in Lawrence. He convinces Dean that the nightmare was a premonition and insists that they need to go back there. Dean's not happy but finally agrees. They arrive at the house and after talking to them for a while, find out that the house is clearly haunted. Clearly disturbed by this, they start to plan how best to investigate.
Meanwhile, back at Jenny's house, a plumber is called in to look at the blocked sink. He ensures that the waste disposal is switched off, but when he sticks his arm in, it somehow switches itself back in, shredding his arm.
Dean and Sam start asking around, looking further into the history of their old house. They talk to one of John's old partners (possibly Mike) and find out that his friends believed he had gone crazy after the fire and had started seeing a psychic. Dean and Sam go to visit her, Missouri Mosely, and are shocked to find out that she has met them before, when John brought them to see her after Mary's death. She tells them what she knows about the demon that killed Mary.
At Jenny's something traps Richie in the refrigerator, although he is found in time by his mother. Dean and Sam arrive with Missouri and explain to Jenny that the strange things that have been happening are due to the house being haunted. Missouri senses two spirits in the house : one is a very malicious poltergiest but she cannot identify the other one. She is sure, however, that it isn't the same thing that killed Mary. She tells the boys that the house has become a magnet for the paranormal. They attempt to banish the spirits, purifying the house, but as soon as they start, they are attacked by the poltergiest who almost manages to kill Sam.
They finally finish the ritual and Missouri belives that the spirit has been banished. Sam isn't convinced and waits outside the house with Dean. He's right and Jenny gets attacked by the same spirit. They manage to get Jenny and her children out of the house but Sam is trapped by the poltergiest. Suddenly, the flaming ghost from Sari's closet arrives. Sam recognises it as it takes on human form again - it's Mary, their mother. She takes a moment to look at her boys, saying nothing more than their names and "I'm Sorry". She then confronts the poltergiest and defeats it, freeing the boys.
Missouri confirms that the spirits are truly gone now. She explains to Sam that his mother's spirit destroyed herself to protect them. The boys say goodbye and leave, while Missouri goes back home, where she speaks to her other guest - John Winchester.