[I]Four Years Ago: Coeur d’Alene, Idaho[/I]
Nora Havelock, a Wiccan, drives out to a cabin in the woods and Sam greets her at the door. He warns her that she shouldn’t have come but Nora explains that she had to be there after everything that she experienced. They go to see Dean, who is preparing to torture a demon-possessed postal worker, Jeffrey. One of its victims is dead on the floor. When Nora tells the demon to go to hell, it promises that it will track her down and kill her when it returns. Frightened, Nora leaves the cabin.
As Sam and Dean warn the demon that they’ll torture it if it doesn’t tell them where they can find Lilith, the demon lets Jeffrey speak. He tells them to stop them demon but begs them not to hurt him. Sam admits that to torture the demon, they’ll have to hurt Jeffrey as well. He tells them to do is so that they can stop the demon, and then demon reasserts control. The brothers use holy water and the demon-killing knife to torture the demon and it finally gives them a name and a place: Merrick in New Orleans. Dean then casts an exorcism ritual, driving the demon out of Jeffrey’s body. While Sam cleans up, Dean drops Jeffrey off at the local hospital and warns him not to tell anyone what really happened. As Dean drives off, the battered, bleeding Jeffrey mutters, “Thank you.”
Dean and Sam return to Coeur d’Alene, check into a hotel, and get a call from Frank. While Dean gets an update on the Leviathans, Sam continues to have hallucinations of Lucifer but refuses to acknowledge when Lucifer talks to him. When it persists, Sam prods the wound on his palm and the pain drives the hallucination away. Meanwhile, Dean hangs up and tells Sam that Frank hasn’t had any luck finding Dick Roman. They’ve returned because two women have been murdered the same way that the others were killed four years ago by the demon. Dean is more concerned about dealing with the Leviathans, but gives in when Sam reminds him that they were the ones who thought the demon was gone, and now they have to clean up.
The brothers hear about a third murder via the police scanner and go to the crime scene. They meet with Detective Sutton, who remembers them from four years ago when they worked the case posing as FBI agents. Sam finds sulfur at the crime scene and they figure that the same demon is responsible. They go to visit Nora at her magic shop, and she shows them the demon traps and banishment spells that she has prepared. However, she figures that the Winchesters can handle it and plans to leave town. Nora suggests that the demon has somehow returned and suggests it might be using Jeffrey as its host.
Jeffrey is staying at a halfway home for psychiatric patients. The group manager, Alan, is hosting a therapy session and Jeffrey tells the others that he’s getting a dog from a shelter and insists that he’s ready to take responsibility for his life. After he picks up the spayed dog at the shelter, Jeffrey walks home and carefully goes down an alleyway, Sam and Dean grab him and make sure that he’s not demon possessed. They then go back with Jeffrey to his apartment at the home. As Sam tries to reassure Jeffrey, Lucifer appears to him again. When Sam prepares to use the pain to make Lucifer disappear, Lucifer gives up for the moment and disappears on his own. Dean explains what has happened and the Winchesters promise to protect Jeffrey. Jeffrey asks what the name of the last victim was, and then tells them that the demon used to recite a list of his intended victims. The next person on the list is Marjorie Willis. Dean points out that it doesn’t make sense that the demon is acting like a serial killer rather than a demon, and Jeffrey says that the demon said it was his job. Alan comes by and Jeffrey claims that his visitors are fellow post office workers from before he had his breakdown. The brothers listen and Dean sympathizes with Jeffrey, who is stuck with someone watching over him Once Alan leaves, Dean stays to watch Jeffrey while Sam goes to the library where Marjorie works.
As they wait, Jeffrey explains that after he was hospitalized, he lost his job and his health insurance. He started drinking and had a mental breakdown, and then started talking about what really happened. Jeffrey was committed and is finally out after four years. Dean point out that no matter what Jeffrey went through, he got out. He apologizes to Jeffrey, but the former postal worker says that he’s the one who owes Dean for saving his life. He then explains that the demon had a special place where it nested and kept its “souvenirs,” and that he wants to take Dean there.
Sam goes to the library and keeps an eye on Marjorie. Lucifer keeps trying to get Sam to acknowledge him and finally gets bored and makes Sam hallucinate all of the readers bashing their heads in. Sam spots a man in a leather jacket following Marjorie and goes after him.
Jeffrey takes Sam to a warehouse near a train yard and explains that the demon only let him see so much, and they’ll have to search from there. He gives his dog some jerky and has him stay in Dean’s car while they start searching.
Sam hears Marjorie moaning in apparent pain, but discovers that she’s making out with her lover, the man in the leather jacket.
Dean and Jeffrey make their way into a warehouse and find a room covered with demonic symbols. There’s a young man chained to a chair and Dean goes to free him. He has no idea who the man is, but before he can free him, Jeffrey injects Dean with a sedative and knocks him out.
At the library, Sam calls Dean’s cell phones without success. As he goes over the coroner’s report, Lucifer points out that all of the victims had tranquilizers in their system, but a demon with superhuman strength wouldn’t have needed drugs to subdue its victims. Sam finally tells Lucifer to shut up and then goes to Jeffrey’s apartment. He finds a box for a cell phone scrambler and Lucifer suggests that Jeffrey is using it to block Dean’s calls. Sam finally locates a secret compartment containing a scroll with a spell in a familiar handwriting. They go to Nora’s shop and break in, and she attacks Sam. He takes her down and demands to know why she wrote a demon-summoning spell for Jeffrey. Nora refuses to talk until Sam threatens her, and then she explains that Jeffrey has her son and the demon never came back..
Dean wakes up and realizes that Jeffrey tied him to a chair and seated him next to Nora’s son. Jeffrey tells Dean that he loved being possessed and he loved the demon, and he never wanted the Winchesters to save him. As he prepares Nora’s ritual, Dean realizes that Jeffrey is and was the serial killer all along. Jeffrey tells him that the demon taught him how to kill, unleashing his full potential. He was attracted to all of the women and made up his list, but didn’t act on it until the demon gave him the willpower to follow through on his darkest desires.
Nora tells Sam that Jeffrey came to her and asked for the ritual. When she refused, Jeffrey kidnapped her son and demanded that Nora do the ritual. However, it didn’t work and he cut off her son’s ear and sent it to her. Sam figures that the ritual didn’t work because the demon is imprisoned in Hell for betraying his superior. Nora came up with a more powerful spell, one that requires the blood of the exorcist that originally banished it. Sam realizes that Jeffrey is going after Dean and tells Nora to use her son’s ear for a tracking spell.
Jeffrey cuts Dean and takes some of his blood for his ritual, and says that he understands Dean after seeing him in action. He figures that Dean suffers because he sees people being hurt and can’t do anything about it. Dean angrily denies it but Jeffrey explains that thanks to Alan’s coaching, he’s taken responsibility for his life. He cuts the heart out of his new dog and then puts it in a chalice and pours Dean’s blood on it. Jeffrey recites the summoning spell and the entire building shakes... and then the demon enters Nora’s son.
The demon shrugs off the chains and embraces Jeffrey, thanking him for his help. He then dances with him and tells the killer that he’s learned his lessons. Jeffrey is disappointed that the demon didn’t possess him again, and the demon tells him that he’s ready to act on his own. Jeffrey refuses, insisting that the demon possess him, and the demon slaps him to the ground. He admits to Dean that he’s on Earth as a talent agent, finding people with potential and turning them into the next generation of superstar killers before they get to Hell. It plans to kill Nora’s son once it’s through the with the body since there’s no potential there.
Sam arrives and attacks the demon, which knocks him back. Dean manages to cut through his ropes and the demon goes after them, only to realize that Sam has lured him into the demon trap on the ceiling that Nora has drawn. When Jeffrey goes to the demon, Dean shoots him dead. As Nora casts the spell to send the demon back, it promises that it will be back to gets its revenge.
Back at the motel, Sam wonders how Jeffrey could have convinced them he was normal. His brother tells him that psychopath act normal just like everyone else. As he dozes off, Lucifer tells Sam that he won’t be sleeping and that it’s time for them to talk. When Sam tries to send him away, he discovers that he can’t. Lucifer explains that Sam invited him in and can’t send him away, and fills Sam’s minds with images of flames while he laughs in triumph.