Moe's Tavern is the scene of merry-making for the people of Springfield, and Moe relates how his role as bartender gives him insight into his customers' lives. He notices tension in the marriages of Homer, who argues about what to do for Mother's Day, Apu, who plays a song in the car that Manjula dislikes, and Reverend Lovejoy, who does not want to help Helen because he is playing with a train set. Mother's Day is approaching, and Marge suggests that Homer take the children to Weasel Island after Krusty the Clown suggests it on his show (so that the mothers can have a break), and it leads into the aforementioned argument. At first Homer is enthusiastic, but becomes concerned when Marge mentions his leaving will allow her to "take care of something." As the ferry to the island pulls away from the dock, the three men receive a letter from Moe informing them that he is running off with one of their wives.
At Weasel Island, the children spend time at a shoddy amusement park while Homer, Apu and Lovejoy agonize over their situation. At first, each insists their marriage is fine. Homer, however, remembers his mother-in-law's 80th birthday, where Moe was the bartender. Homer, who was angry at Marge for only serving non-alcoholic beer, got into an argument with Patty and Selma after they start annoying him with their antics. Disgusted, Homer then drives them out, and Marge told him that he ruins every event that she plans. Apu notices cracks in his marriage, recollecting an incident where he and Manjula forgot their son Gheet at Moe's after using the bar's bathroom to change out of rain-soaked cricket uniforms. Manjula drove back to retrieve their son and did not return for hours. Homer mentions that he saw Manjula playing an interactive dance video game with Moe that night. Finally, Lovejoy remembers advice given to him by the Parson that he ignored his wife Helen's needs, and Apu recounts how he witnessed Moe confiding in Helen that he was in love with a married woman and that Helen put her hand on his knee.
When the ferry returns to the mainland, each man realizes that they are equally likely to have lost their wives to Moe. Otto drops Homer and his kids off first. At first, Homer thinks Marge is packing a suitcase and tries to convince her to stay. Once he comes in, he realizes that she has painted a portrait of her mother. Her mother, Mrs. Bouvier, tells Homer that he was not responsible for the 80th birthday incident. She admitted that it is Patty and Selma's fault because there is "something evil" about them (they even smoked during her pregnancy). This may indicate that she has finally overcome her disgust for him. While watching Homer and Marge make up, both men slump in their seats, thinking it is either Helen or Manjula that left with Moe. Otto informs Rev. Lovejoy that his house is the next stop. However, Kirk Van Houten tells him that he and Milhouse are the next stop. Otto scoffs and reminds him that there is nothing suspenseful at his house, including that he had sex with his wife, Luann. When Rev. Lovejoy arrives home with Jessica, he too thinks Helen is leaving, but instead she surprises him with tickets to Istanbul on board the Orient Express. By process of elimination, Apu concludes that his wife has left. He arrives home with their octuplets to find Moe sitting with Manjula, but she tells Apu that he convinced her to salvage their marriage.
In the end, Moe reveals that he saw how troubling the relationships were, so he organized Marge's portrait, the Lovejoys' trip and the Nahasapeemapetilons' marriage rescue. He explained that he wrote the horrible letter because the three men were taking their wives for granted, saying that they need to value them more just like their other family members. Upon learning this, Homer admits that he does not know whether to punch or kiss Moe, but eventually decides to do both as a thanks for teaching him that lesson. In the end, Moe then implores viewers to value their wives and mothers. The song featured in the end credits is the 1973 hit "I'll Always Love My Mama" by The Intruders.