After Homer wrecks both of the family cars in a snowstorm, he purchases a snowplow truck and uses it to start a business as "Mr. Plow," which proves to be surprisingly successful. Things go well for Homer until Barney starts his own goatplow business ("The Plow King"), competing with Homer, and steals all of Homer's customers.
A blizzard hits Springfield, so Marge calls Homer at Moe's Tavern and tells him to come home right away. Homer drives through the snowstorm and manages to wreck both of the family cars when he rear-ends Marge's car in the driveway. Marge, Bart, Lisa and Maggie are in the front door waiting for him was shocked at what happened. Homer then lies to an insurance claims adjuster about his whereabouts before the accident in order to cover the fact that he was coming home from a bar.
The insurance company pays the claim, and Homer goes to a car show to get a new car. A salesman talks Homer into getting a snowplow because he can afford the higher payments by doing plowing jobs on the side. Homer buys the snowplow and starts his snow plow business as "Mr. Plow". With the help of a late-night TV ad, Homer's business is an instant success, winning the respect of the whole town. In recognition of the achievement, Mayor Quimby gives Homer a key to the city.
Barney, who has been working at a succession of dead-end jobs, asks Homer how he can be a success, so Homer tells him to go out and be the best Barney he can be. The next day Barney has bought a bigger plow, and goes into business for himself as "The Plow King". With Linda Ronstadt's help, Barney creates his own ad (denouncing Mr. Plow as an alcoholic loser) and steals all of Homer's customers. Mayor Quimby then takes back the key to the city from Homer and gives it to Barney. To get revenge, Homer tricks Barney into going on a fake plow job at the top of a mountain called Widow's Peak.
While Barney is gone up the mountain, Homer begins to plow driveways again. However, the news later reports there has been an avalanche on Widow's Peak. Homer, feeling guilty, sets out to rescue Barney, and in the end they agree to become partners. Their claim that not even God could stop them brings about a response from God—the melting of the snow. With no more business, and no way to make the payments, Homer's plow is repossessed at the end of the episode, but that doesn't stop Marge from enjoying Homer wear his Mr. Plow jacket to bed.