When Homer gets a baseball card of Joe DiMaggio from Mr. Burns for a Christmas bonus he goes to the Android's Dungeon to sell it. Not knowing that the card is rare and worth a lot of money Comic Book Guy unloads the register and hands over everything he’s got to Homer. When Homer goes home with all his money he tells the family that they’re going to the Springfield Heights Promenade. Homer buys the Astrolabe with all his money that he promised would go towards buying a huge Christmas tree. On Christmas morning Marge discovers the astrolabe and Homer is shunned from the family. Homer is forced to sleep on the couch while Marge is mad at him.
Homer tunes into a show called Mr. McGrew's Christmas Carol which shows him how selfish he is and decides to change his ways. He then dubs himself "the nicest man in town." Flanders goes to give some hobos clothes and food, until he sees Homer has already done that. His other good deeds include giving Lenny a photo cube with pictures of them to make up for his lame present. He gives Marge the last pork chop and builds an ice-skating rink in the backyard for all to enjoy. Ned becomes jealous of Homer because of this. After being one-upped by Homer, Ned tries to earn his rightful spot as "nicest man in town" by buying everyone in town presents (thanks to renting his house out to a fraternity). Homer tries to think of a way to do better than that, but Lisa reminds him of her Buddhist ways and how they believe that Christmas isn't about material goods. That makes Homer think and decides to follow her advice by stealing back the presents under the cover of nightfall (à la How the Grinch Stole Christmas!). In the morning, everyone finds their presents are gone and riot against Homer, until they see a star in the sky (which is actually a flare set off by Hans Moleman who's trapped in the snow). All lose their rage and join hands to sing Hark! The Harald Angels Sing as Snake comes by and steals the Astrolabe.