Preparing for Topanga to spend Christmas with his family, Cory shows Eric a promise ring that he had gotten for her. But things quickly turn sour when Topanga imposes her family traditions on theirs. They drink cider instead of eggnog. They drive to Vermont to buy a real Christmas tree instead of their traditional aluminum one. She suggests they act out "A Christmas Carol" instead of Feeny's traditional reading. She even wakes up in the middle of the night to talk to Cory (who is hoping that she has come to sleep with him, but is wrong), something Cory has never once done. Of course, now Cory can't sleep. He wanders downstairs and finds Alan awake as well. Alan tells him that Amy has waken him up in the middle of the night just to talk for many years. After she goes back to sleep and he can't he works on airplane models. He hands Cory a model plane, and tells him he's been saving one for each of his sons.
The next morning, things don't get any better. Topanga makes Cory Christmas tree shaped pancakes, but insists on using powdered sugar instead of syrup. She also wants to go caroling, something Cory hates. Frustrated, Cory tells her he doesn't want to take part in her traditions. He goes off to Shawn's apartment to think, where Shawn tells him to go back home to Topanga. Cory refuses, showing Shawn the promise ring and telling him he's recently learned just how different he and Topanga are. Shawn tells him that while he and Topanga are different, they're meant to be together, while also bringing up that he and Jack have nothing in common with one another, as this is their first Christmas together. Then, Topanga enters and apologizes for imposing her traditions on him. She says she'll wait for him at his house. Shawn again suggests that Cory go with her, but Cory decides to watch "A Christmas Carol" on TV to think instead. Shawn then announces he's going ice skating, which surprises Jack, who tells him that he loves ice skating as well. The brothers are finally happy to have something in common, and set out to the skating rink.
As Cory dozes off, he is awakened by Feeny. Only, it isn't Feeny. It is The Ghost of Christmas Future, who looks just like Feeny in a doorman's outfit. Feeny takes Cory to the future that would occur if Cory stayed on his current path. He'd be living with Eric, who would be bald, and he'd only eat Christmas tree shaped pancakes with powdered sugar. Also, Cory would be fat and lonely. Cory demands to be taken to see what happens to Topanga, and Feeny obliges. In the future, Topanga is married to Jack and they have three kids. Even though the kids open the presents on Christmas Eve, Topanga's way, Feeny points out that they have an aluminum tree. Cory begs Topanga's forgiveness, but Feeny tells him she can't hear him. Cory feels lost, and Feeny takes him home.
At the Matthews' house, Topanga waits for Cory. She tells Amy she feels guilty for pushing Cory away, and says she only wanted to be a part of their Christmas. Cory then shows up, singing a Christmas carol through the door. He apologizes and gives Topanga the ring. Topanga gives him his gift also, which is another promise ring. That night, Feeny reads everyone (including Shawn and Jack) "A Christmas Carol," but they're all asleep by the time he finished. He shuts the book angrily, saying "Bah, humbug!"