Homer and Marge attempt to work on their marriage, not realizing that Mr. Burns and Nigel have a bet on whether Nigel can bisect them apart. With the successful, albeit unconventional, help of Moe, the couple gets back their mojo.
Marge and the kids are waiting for Homer to arrive home and join them for Sunday dinner, but arrives after crashing into the Flanders' mail box and sending it crashing through the window, leaving Marge to silently reflect her rage with her husband's behavior. At the Nuclear Power Plant, while Homer, Lenny and Carl talk about how Marge did not react terribly to what happened, Mr. Burns introduces them to Nigel and his wife. Homer tells Marge that their marriage is "on E, but there's still a little gas left" when she shows up with a picnic lunch, where Homer surprises her by actually eating a carrot. Nigel plans to offer Burns a wager of five million pounds that he can sabotage their marriage, and Burns, who has had a long history of observing his employee, gleefully accepts.
After the shift at the power plant ends, Nigel pressures Homer into breaking his plans into going home to Marge by stating that Homer needs to go home Moe's with him or else Burns will not be pleased. In a lingerie-clad Marge does not understand Homer's "Drinking with a British guy" emjois and she is felling hurt after looking out the window for Homer only to see Disco Stu dancing with woman, Clancy Wiggum giving his wife Sarah jewelry from the evidence box, and Ned Flanders giving harps to the poltergeists of Edna Krabappel and Maude Flanders. Homer and Nigel are at Moe's Tavern and Nigel keeps pushing Homer into breaking away from Marge, but Homer's love for Marge is too strong and goes back home to her, after punching Moe when he finds out Marge is the "Midge" Moe always refers to. Nigel then explains that he has a way to separate the Simpson couple and make money in the process.
Back at home, Marge refuses to listen to Homer and goes to bed, sobbing all night. The next morning, Marge is still offended with Homer and tells him to go to a ballgame with Ned because she does not want to talk to him. While heading home from the game, Homer notices that Moe's Tavern is closed. Moe arrives in a fancy car tells them he got set up by Nigel at a new 104th-floor super-exclusive bar called MoHo House. At the grand opening of Moho House, Homer and Marge part ways at the center, and Nigel raise up the bet, betting has whole fortune against the rights to aghast Smithers and Burns accepts. Moe is able to charm Marge while he dances with her, while Smithers gives Homer the gift he had been planning to give his mother to keep Nigel from winning the bet. Moe runs off when it seems Marge might interested in him, but a bartenders' advice to Marge about how Homer treats her the same way over time because he likes the way their relationship is backfires big time when Marge misinterprets Homer's offering of Smithers' gift.
Homer tries to give her the gift but Marge sees its not for her (Homer didn't change the card which wished a happy eighty first Birthday to Smithers' mother), and ignores Homer's pleas to forgive him. At MoHo House, Moe listens to a blues pianist who says via song that his effort to trash the Simpsons' marriage is wrong. Moe later texts Marge to meet him at the place, and then Homer, who shows up dipleased, but then listens to Moe's message (after Moe apologizes to Marge for always calling her Midge): Moe will never steal Marge from Homer, but someone else will if Homer doesn't start treating her well consistently. Homer offers a cute cartoon of him and Marge, and she has won over again. The two make peace, and Burns wins the bet but Smithers (who was furious at being wagered again by Burns) gives false information that Nigel is a figment of his imagination and that the check was a fro-yo coupon, leading Burns to tear up the check. To thank him, Nigel gives Smithers a kiss on the lips. As the episode finishes, Moe returns to his old dive tavern and an elated Barney, while Burns agrees to a better employee contract with Smithers.