The Simpsons go to the Springfield Googelplex Movie Theaters to see The Poke of Zorro which had intentional historic inaccuracies. Afterwards, Homer, imitating Zorro, frightens Snake away by challenging him to a duel by slapping him with a glove when he insults Marge; he then starts to use his dueling glove to get anything he wants from people. First up is Moe for calling him heavyset, but after a slap, he gives Homer a free beer. When a gun-toting Southern colonel at the Kwik-E-Mart actually "accepts" Homer's challenge, Homer finds himself bound to a duel at dawn the following day.
With Homer fearing for his life, Marge tries to assure him the colonel won't show up. Bart insults Homer over it, who is about to challenge him to a duel in return; however, his family stares at him because he didn't learn his lesson. The next morning, the colonel does show up, he and his wife having arrived outside the house in their RV. The Simpsons sneak out with Homer clinging to an old Christmas tree and search for a temporary home. They encounter former President Jimmy Carter at a Habitat for Humanity site. Lisa humbly requests that Carter build them a home, but he replies the houses they build are for the truly needy. Homer angrily demands that Carter comply, who is offended and about to glove-slap Homer to challenge him to a duel. But having learned his lesson by then, Homer screams and speeds off before Carter can administer the glove.
They find Grampa's old farmhouse (even though the end of "Grampa vs. Sexual Inadequacy" saw the old farmhouse burning down after Homer dropped a match and Grampa threw the sex tonic into the fireplace) on Rural Route 9 outside of Springfield, where they decide to live and, despite the land's poor reputation for growing crops, Homer becomes a farmer. After failing to grow a thing, Homer calls Lenny and requests that they send plutonium to make the crops grow "real big, real fast." They do eventually grow, but since Homer had accidentally mixed the tomato seeds with the tobacco seeds, he decides to call the tomato-cross with tobacco, Tomacco. Homer and Marge set up a stall, Homer providing tomacco and Marge, fresh-baked mincemeat pie. While the pies do not sell well, the tomacco is such a success that executives from Laramie Cigarettes offer to buy the rights to Tomacco for $150 million because they "want to sell tobacco to kids."
Lisa protests that the Simpsons cannot accept the tobacco executives' money, but Homer misinterprets this statement, and rejects the offer as insulting, demanding $150 billion for tomacco, which they refuse to pay. Dumped back at the farmhouse, the family sees tomacco-addicted animals from other farms eating their crops. Homer saves the last plant by tricking a cow into thinking that there was a flying saucer present and the family run into the house to discuss what to do with it. Lisa urges Homer to destroy it so the world won't be addicted to the drug but Homer says he cannot do it because he is "just one man!" The neighbouring livestock track the smell into the farm house and break in, he tosses it into the air, and it lands right in the hands of a Laramie executive. The Laramie executives' helicopter leaves, but a tomacco-addicted sheep has sneaked on board and attacks them. The helicopter crashes, killing everyone on board except for the sheep and destroying the final tomacco plant. The Simpsons return home from the chaos, only to find that the Southern gentleman and his wife are still waiting for Homer to go through the duel. Homer does, but ends up getting shot in the arm, and declines to go to the hospital until after eating one of Marge's mincemeat pies.