Homer, Bart, and Lisa see the newest Cosmic Wars film, The Gathering Shadow, and the movie turns out to be less than what they expected. At home, Marge suggests that Bart and Lisa write a letter to Cosmic Wars creator Randall Curtis. Two weeks later, they get a reply from Curtis, which completely ignores their criticism, having sent them Jim-Jam merchandise. This forces the Simpsons to go on a trip to California, where Homer and Marge go to wineries, and Bart and Lisa go to the Cosmic Wars Ranch.
Bart and Lisa visit Curtis and tell him that his Cosmic Wars movies have lost their way. He does not like what they are saying until Lisa points out that better technology is no way to make the story better. Curtis agrees, and he decides to go back to his storytelling roots.
Bart and Lisa rejoin Homer and Marge, who are both drunk from free samples of the wine. Back in Springfield, Homer and Marge go to Moe's Tavern and drink more wine. Moe opens a bottle of Chateau Latour 1886 vintage wine, clearly unaware of its value. Homer and Marge then continue to drink heavily for several days, until Marge suffers a particularly painful hangover. She tells Homer that they should not be drinking, and he agrees. Unfortunately, when they go to an Oktoberfest featuring Grammy-winning nuclear polka band Brave Combo, Marge, who tries to go through the night without drinking, gives in and ends up drunk along with Homer. He tries to drive them home, but in a drunken stupor overturns the car.
In order to avoid an arrest, Homer makes things look like Marge (who is drunker than he is) was the driver. She is arrested, but he bails her out. Later, Barney suggests that Marge go to a rehab clinic for a month, and when Marge is gone, Homer lets Flanders take care of the kids. When he sees her at the clinic, he confesses, but Marge is angry and drinks again. Later on, the other rehab patients help her discover that she likes being with Homer more than she likes drinking, and forgives him and returns home.