Dean and Sam make their annual trip to Las Vegas, and Sam goes camping on his own while his brother visits a strip bar. He chats with a waitress, Kelly, and describes his situation with Sam. Kelly suggests that Sam might need some time on his own. Before Dean can follow up with her, he gets a call from Sam from four blocks away, telling him to show up and wear a suit. Dean discovers the address is a wedding chapel and the lights flicker as he enters. He goes to the chapel and finds Sam waiting for him, wearing a suit with a carnation. As Sam pins a carnation on him, Dean wonders if they’re looking for a Siren but his brother says it’s nothing like that. He then tells Dean that he’s fallen in love and getting married. Before Dean can get an explanation, the bride comes in: Supernatural super-fan Becky Rosen.
Dean is less than thrilled with the news and Sam explains that they met, ate, talked, and fell in love. He’s already confirmed that Becky is who she says. Becky knows about all of Sam’s romances and how they tend to go, but is comfortable with the idea. Sam figures that he needs to leap at the chance since it’s presented itself. When Becky goes to pay the bill, Dean suggests that Becky might have read Chuck’s new book and figured out where Sam was, but Sam explains that he’s going to Delaware to Becky’s home while Dean figures things out.
Dean heads out and calls Bobby to update him on the situation. Meanwhile, the happy couple arrives in Pike Creek, Delaware, and Becky stops off at the hotel hosting her 10-year-reunion. She’s happy to tell snooty classmate Jocelyn Caruso that she’s now married and RSVPs for the reunion, showing off handsome husband Dean. As they head outside, Becky spots her fellow horror novel fan and friend, Guy, an event planner. She introduces Sam and Guy secretly slips her a vial of purple fluid. Becky thanks him, noting that it’s good to have a Wiccan as a friend.
Dean arrives in Pike Creek and goes to a hotel. As he sits at the bar, he notices a newspaper headline about a lottery winner who was then hit by a truck and killed.
That night, Sam and Becky have their first dinner and she offers a toast to the two of them. Sam suddenly has a headache and has no idea what’s going on or why he’s with Becky. She sits in his lap, pours some of the purple elixir into his champagne, and makes sure that he drinks it. Once he does, Sam goes back to being a doting husband.
At a local baseball stadium, a man is practicing against a pitching machine, hitting every pitch, while another man, Jackson, watches from the stand. Jackson gestures and the pitching machine goes out of control, killing the batter with high-speed balls.
Dean finally visits the happy couple and gives them a nonstick wedding iron as a gift. He starts to tell Dean about the case of people getting their fondest wishes and then dying only to discover that they’re already working it. Dean figures that Becky is up to something and points out that Sam isn’t acting normally, but Becky says that they’re just happy and Sam agrees. However, Dean warns him that the people getting their fantasies soon die, and Becky could be next. Sam suggests that he went after Dean, and that it’s bugging him that Sam is moving on with his life and doesn’t need his big brother to take care of him anymore. Dean walks out, but calls Bobby for help. Bobby is tied up and sends him to another hunter.
Becky is in her room writing Sam’s name down over and over in her diary. He comes in and she hides it, and Sam gives her new fake IDs so they can go monster-hunting together. Sam has figured that a junior salesman that became CEO in a few days is the next potential victim. He finds her diary but isn’t creeped out.
Dean meets his new hunter/partner at the hotel bar. It’s a skinny geek, Garth, who knows all about Dean. Dean shows him the case on the new CEO, Craig Burrows, and they head out after Garth checks out the cartoons. They go to Craig’s office and overhear his wife, Marsha, berating his assistant for misspelling her name. Sam and Becky come out of Craig’s office and tell Dean that Craig is clean. Dean explains that he has a temp partner and goes in anyway. Garth bluntly asks him if he’s been using black magic, and Dean tries to cover. Craig admits that he has no idea why the board chose him, and that getting promoted wasn’t his big dream. Marsha comes in to complain about his assistant and then leaves, and Craig admits that she’s been happy about his promotion. Dean and Garth go after Marsha and Dean tries to warn her. He’s not very convincing and she storms off.
As Sam and Becky work on the case, Sam gets another headache. Becky discovers that she’s out of elixir.
Marsha goes to the lobby to make a call, and Jackson makes a mystic gesture to drop a mobile on her. Dean arrives just in time to save her and she admits that she made a deal with a guy who offered her Craig’s job in return for her soul. Garth points out that demon deals guarantee ten years of satisfaction and offers to hide Martha with his cousin so they can find Sam.
Sam starts remembering what really happened while Becky tries to call Guy. When he tries to call Dean, Becky knocks him out with Dean’s waffle iron. When Sam wakes up, he discovers that Becky has taken off his pants and tied him to a bed. Guy finally calls Becky back on the laptop and she goes to the next room to take the call. She asks for a refill, pointing out that it’s wearing off faster and faster, and Guy tells her to meet him in an hour. Becky goes back to Sam, who has overheard the entire thing and accuses her of dosing him with a love potion. He tries to warn her that Guy is killing the others but Becky insists that he’s a Wiccan, not a witch. Sam figures that she’s next on Guy’s hit list, and suggests that if she love Sam then she free him. She gags him and leaves.
Becky meets Guy at the high school reunion hall and he tells her that now she has to pay for the elixir... with her soul. He reveals that he’s a crossroads demon and insists that his clients had accidents but he didn’t kill them. Guy promises that he won’t kill her after she makes her deal, and offers her 25 years of happiness as long as she promises not to tell anyone what happened. After a moment, Becky agrees to consider it
Dean and Garth break into Becky’s apartment and discover that the couple is gone. Garth checks her twitter account and her announcement that she and Sam are going on a honeymoon trip. Dean finds a photograph of Becky in front of her parents’ cabin, with an address on the back.
Becky goes back to the cabin and tells Sam about how she planned to show him off at the reunion. She tells him that she’s a loser and a freak, and that Chuck dumped her, and she wants someone who loves her for herself. Becky finally ungags Dean and he tells her that she’d have better luck finding someone if she didn’t drug him. She says that she doesn’t have any other way and takes out the elixir.
Once the reunion is over, Becky goes back and tells Guy that she’s accepting his deal. However, as she prepares to seal the deal with a kiss, Becky lights her lighter and tosses it onto the carpet, revealing that Garth inscribed a pentagram with blueberry vodka. Sam, Dean, and Garth come in, and Dean takes out the demon-killing knife. Guy explains that he doesn’t kill any of his clients, but he found a loophole. If someone else creates an accident, he gets to collet early. Jackson, his intent,” comes in and throws the three hunters back, and then breaks the pentagram. Dean tries to exorcise Guy while Sam struggles with Jackson. Becky gets the knife and stabs Jackson, and Sam tosses the knife to Dean. Dean puts the knife to Guy’s throat and tells him to break his 15 remaining deals.
Before Guy can respond, Crowley teleports in and explains that Jackson betrayed Guy. He informs his demon that they never call their chits in earlier because it sends the message that no one can trust them. Crowley tells Dean to hand Guy over, he’ll cancel the deals, and then make an example of Guy. When Sam asks why he’s helping them, Crowley explains that he’s told his demons to stay clear of them so that they could destroy the Leviathans. He wishes the brothers luck, destroys the contracts, and teleports away with Guy.
Later, Sam and Becky sign the annulment papers. Sam admits that Becky saved him from Jackson but tells her that they won’t be meeting again. He tells her to be herself and the right guy will find her, and she and Guy share a meaningful look.
Outside, Dean admits that Guy doesn’t suck and Guy hugs him. A lot. Once Guy leaves, Sam apologizes for what he said when he was dosed up. When Dean says that Sam is handling his hallucinations, Sam says that he has a handle on it. Dean figures that Sam doesn’t need him around all the time and can handle things. As they leave, Sam says that it’ll be nice for Dean to take care of himself, but Dean doesn’t appear comfortable with the idea.