Kevin goes about his duties on Garth's boast, working to translate the tablet. He wakes up at 5 and goes to bed at 2:45 every day for over a month, taking pills to keep his headaches under control. Finally he translate the tablet and stares at it in surprise and pleasure... and then collapses, his nose bleeding.
Dean is settling into his new quarters at the Letters' base, making sure everything is to his liking. When Sam comes in, he listens as Dean talks about having an actual bedroom for the first time in years. When Dean goes to get some food, Sam looks around and sees the photo of their mother that Dean has put on the desk. Sam then goes to the main room and goes through the library. Dean brings in some food that he's cooked himself and tells his brother that he's been nesting. As Sam starts eating, Kevin calls Dean and tells him to come quick.
When the brothers arrive at the boat, they find Kevin throwing up in the bathroom. He tells them that his health hasn't been good and he may have had a stroke, but it's worth it because he's translated the tablet. The tablet contains a spell which has to be recited after completing each of three trials created by God. So far Kevin has only translated one of the three trials, and explains that it describes how the subject must kill a hellhound and bathe in its blood. Since hellhounds collect the damned ten years after they make a deal, Sam starts checking the Internet for successful people and odd demon signs. When Dean goes into town to get food for Kevin, Sam tells Kevin that he needs to relax. He warns that saving the world is a long-time duty and Kevin can't afford to wear himself out too soon. Kevin disagrees, insisting that he needs to figure out how to close the gates to Hell so that he can have a normal life.
When Dean returns with food, Sam has learned that there were demon signs ten years ago in Shoshone, Idaho. At the same time, a family of small-time farmers, the Cassitys, struck oil on their land. Dean gives Kevin aspirin and pep pills to keep him going and leaves with Sam.
When the Winchesters arrive at the Cassity ranch, they approach the manager, Ellie. She assumes that they're drifters looking for work and they play along. Carl Granville, Alice Cassity's husband, comes over and tells Ellie to hire the Winchesters. She takes them to the bunkhouse and then puts them to work mucking out the horse stalls. As they work, they hear Ellie arguing with Alice over how to run the ranch. Once Allie leaves, Ellie comes over and admits that she's not happy with how Alice runs the ranch but she's the boss. Dean suggests that they might get a drink together but Ellie ignores him and walks off. Once they're alone, the brothers figure that since Alice is the successful boss, she must be the one who made the crossroads deal.
That night, Carl and Alice are having dinner on the patio when they hear a wolf howling in the distance. The horses start whinnying and Alice goes to check on them. Dean and Sam follower her... unaware that a hellhound is attacking Carl.
When Alice returns, she finds her husband's body and calls the sheriff. He suggests that a wolf was responsible but Ellie doesn't believe it. As she goes to call the rest of the family for the funeral, the sheriff warns Sam and Dean that the family doesn't get along well. Once they're alone, Dean figures that they've got a dead-end because the hellhound has collected its victim and will move on. He goes to pack while Sam goes to the stable to collect their things. Alice is looking at a horse and Sam asks if she's okay. A puzzled Alice says that she doesn't feel anything about Carl's death and can't remember why she loved him. Sam wonders how they met and Alice explains that she and Carl went to school together but she didn't think anything of him. They met at a party ten years ago and she immediately fell in love with him.
Sam goes back to the bunkhouse and finds Dean looking for the ingredients to make a crossroads deal. Sam warns against it, pointing out that Crowley will know and sends dozens of hellhounds after them. When Sam tells Dean what happened, they figure that the crossroads demon must have made multiple deals ten years ago with the other Cassitys. Dean agrees to wait and see what happens, but says that if they don't get results in two days then they'll do it his way.
The next day, family elder Noah Cassity arrives with his two daughters, Cindy and Margot. Ellie looks on with Sam and Dean and explains that Noah has married five times and has had a younger wife each time. Cindy is a failed country singer and Margot run away to live in Paris just before Carl and Alice married in 2003. The manager then tells the brothers that she'll need one of them to serve drinks at dinner and one of them to cook.
That night, Dean eagerly runs the grill while Sam pours drinks and listens as a drunken Cindy mocks her three family members. Margot sympathizes with Alice, who still feels nothing over Carl's death. Cindy tells Alice that Margot slept with Carl, but the youngest daughter insist that it was before Carl and Alice got together. Sam goes out into the kitchen to get more drinks and runs into Ellie. He wonders how she puts up with the family, and she admits that she doesn't really care what goes on between them and just focuses on the ranch.
As they eat, the Cassitys admits that they haven't had such a good meal in ten years, ever since a travelling salesman visited the farm. They finally remember that the salesman's name was Crowley and Sam, overhearing them, tells Dean what's going on. They figure that Crowley made multiple deals and sent the hellhound to collect. As they talk, Kevin calls to tell the Winchesters that he's found a way to see the invisible hellhounds. The ritual involves covering glass with burning holy oil. Sam goes back inside to watch the Cassitys while Dean gets some holy oil from the Impala and finds two old pairs of glasses.
When Sam goes back to the dining room, he discovers that Margot and Noah have grabbed shotguns and gone outside to hunt down what they believe is the wolf that killed Carl. Sam goes after them and suggest that he join them, and Margot gives him her shotgun. Meanwhile, Dean performs the ritual and enchants the two pairs of glasses. However, he quickly puts out the burning oil when Ellie comes over. She invites Dean back to her room so they can have sex, although she admits that she usually doesn't come onto men. When Dean says that he can't, Ellie retreats and Dean assures her that he'd take a rain check. However, the ranch manager tells him that it's a one-night offer and leaves.
In the woods, Sam hears something moving and splits off from Noah and Margot. He doubles back but Noah finds him and demands to know where Margot has gone. They hear her scream and follow the noise to where the invisible hellhound is ripping Margot apart. Unable to see it clearly, Sam fires a shot and drives it off, and then takes Noah back to the house.
Back at the house, Dean explains about Crowley and the hellhound and asks which one of them sold their soul. None of the three surviving Cassitys say anything and Sam goes to seal the house with goofer dust. Dean handcuffs the Cassitys to the furniture, explaining that if they made a deal then they'll start to hallucinate as the hellhound approaches. He then draws Sam to the side and tells him to stay in the house while he confronts the hellhound. When Sam objects, Dean explains that in the past, one of them has always had to dial when they've had to perform the big final rituals. He admits that he's just a grunt and that Sam is the one that has the brains and has to survive. Dean insists that he doesn't see a way out for him and wants Sam to have a chance at a normal life, and warns his brother that if he follows him then he'll shoot him in the leg to stop him. he then goes outside, looking for the hellhound, and hears music coming from the barn.
When Sam goes back to the living room, he finds Cindy and Noah arguing. They don't believe in demons but Sam points out that they somehow struck oil on their land when there wasn't any there. Thinking, Alice remembers that Margot wanted wealth for the family, figuring that they'd be happy.
Dean follows the music to Ellie's room in the barn. She's dancing and tells Dean that he's just in time. When she tries to kiss him, Dean explains about the hellhound. Ellie says that she knows about the hellhound because it's coming for her.
As Sam watches over the Cassitys, he sees the hellhound outside in the woods. While he's distracted, Alice manages to slip out of her handcuffs and runs out to her car. Sam goes after her, catches her at the car, and pulls her away. The hellhound comes after them and Sam sees it and sends Alice to the house while he tries to spot it using the enchanted glasses.
At the barn, Ellie tells Dean that she grew up at the ranch and met Crowley at the dinner ten years ago. He offered her one wish and she asked for her mother to be cured of Parkinson's. When Dean points out it wasn't a good idea, Ellie angrily says that she would do anything for her mother and asks if Dean would do the same. Dean is surprised to learn that Crowley didn't tell Ellie about the ten-year period, and she admits that she only learned about the deal at all when Carl got drunk one night. Knowing that the hellhound is coming for her no matter what, Ellie has decided not to run. As they talk, the hellhound howls nearby and Ellie stares in horror as Dean's face transforms. He tells her that it's a hallucination and tells her to stay within a circle of goofer dust while he deals with the hellhound.
Dean goes out into the stables and tries to spot the hellhounds. It enters the barn but ducks down behind the crates, and Dean tries to get a fix on it. It jumps him, knocking off the glasses, and then slashes him in the chest. As it approaches him, Sam arrives just in time to shoot it. The hellhound turns and jumps Sam, and he's forced to cut its throat, causing the blood to gush all over him.
Once Dean binds his wounds, the Winchesters go to Ellie and tell her that they'll make her a hex bag. Once she's shielded from Crowley and the hellhounds, she'll have to go on the run so that they can't find her. Dean asks Ellie to step out and Sam points out that Crowley will eventually find Ellie. His brother disagrees, figuring that if they can seal the gates to Hell then Ellie can't be taken there. He takes the spell and recites it, but nothing happens. Dean figures that they can track down another hellhound, but Sam says that he's going to finish the last two trials and seal the gate. He admits that he can see an end for both of them and tells Dean that he trust him, and asks his brother to trust him in return. Dean considers for a moment and then gives Sam the spell. Sam recites it and his right arm glows with red energy for a moment. Once he recovers, Sam tells Dean that he can do it.