The show begins with Homer and Marge Simpson attending the Springfield Elementary School's Christmas Pageant. Lisa performs as part of a group showing Santas of different lands, and Bart sings in the chorus-though with his own rendition of 'Jingle Bells.'
Back at home, Marge finishes writing her Christmas cards, and then looks over the kid's letters to Santa. While Lisa wishes for a pony, Bart wants a tattoo. Later on, Homer puts up some Christmas lights, but only a couple of them light up. Homer is further irritated by Ned Flander's display next door, which is bigger and brighter.
The next day, Homer goes to work and Marge takes the kids Christmas shopping. At work, Homer and a number of other employees are informed that they will not be receiving their Christmas bonuses. At the mall, Bart wanders away from Marge and Lisa, and ends up getting a tattoo. To have it removed, Marge ends up spending all the Christmas money, in hopes that Homer's Christmas bonus will cover the loss. Upon learning that the Christmas money is gone, Homer tries to cover up the fact that he didn't get a bonus, by offering to do the Christmas shopping.
Stopping at Moe's Tavern, Homer sees Barney Gumble appear dressed in a Santa suit, claiming they are looking for part-time workers to play mall Santa's. Homer takes the job in hopes to get more money. While at the mall, Bart attempts to yank off Santa's beard, and soon realizes what Homer is doing.
When Homer and Bart go to collect Homer's paycheck, they are saddened to see that the job only paid $13! As Homer wonders what to do, Barney comes up and invites Homer to come with him to the dog track, in hopes to bet the $13 on a 'sure bet.' Homer is adverse to this, until Bart feels that like Christmas Specials, this could be the miracle that saves their Christmas.
At the dog track, Barney explains that the dog named Whirlwind is the 'sure bet,' but Homer's attention is caught by an announcer that mentions a late entry: a dog named Santa's Little Helper. Homer takes this to be a sign, and bets his money on the late entry. However, this proves to be a big mistake, as the dog comes in dead last.
As Homer and Bart are leaving the track, they see Santa's Little Helper being told to 'get lost' by his owner, for his coming in last again. The dog makes a beeline for Homer, and after Bart pleads to keep him, the two take him home.
Back at the Simpsons house, Homer dejectedly explains to everyone about how he didn't get his Christmas bonus. However, with Santa's Little Helper, the dog ends up making the entire mood just as cheerful.