The Smiths gather around the town square to watch the lighting of the town tree. Roger is drunk and complaining that he's accomplished nothing during his sixty year stay on Earth. Greg and Terry announce that they have to cancel the celebration because the public town square is not a place for religious icons. Stan is furious about losing Christmas and needs his Christmas fill.
He takes them to the mall. Francine and the kids beg Stan to buy Roger a gift because he's so depressed. Stan finds a 99-cent store. Stan finds a best-of disco from 1974 - 1980 cassette.
The Smiths decorate their home, and Stan rants about how the liberals and Jane Fonda ruined the Christmas spirit by making people wish each other "happy holidays." Stan destroys the decorations in the house. Francine forces Stan to sleep on the couch.
That night, Stan is visited by the Ghost of Christmas Past. She takes him to 1970, where he grew up. Stan sees himself as a child, opening toys. When the ghost mentions in 1970 Jane Fonda was filming a movie, Stan runs off to kill Jane Fonda.
Stan makes his way to the movie set.
Also that night, the Ghost of Christmas Past wakes up Francine and tells her that she lost Stan. The ghost tells Francine that she mentioned Jane Fonda and Francine knows exactly where he is.
Stan overhears Donald Sutherland telling Jane to get involved in politics and he knows Jane is no longer the target.
Stan shadows Donald to a fancy restaurant, and sneaks in as a waiter. Stan takes off his jacket, and the disco cassette falls out of his pocket. Working at the same restaurant, Roger in 1970 finds the tape where it fell. Stan checks the bathroom for Donald, instead he finds Martin Scorsese and gets him to kick his marijuana habit.
Francine and the ghost end up in prehistoric times.
Stan overhears Donald telling another woman to get into politics. Stan loads his gun, but before he can kill Donald, the ghost pulls him back. The ghost tells Stan that anything he does in the past could affect the future. She transports herself, Stan and Francine back into the Smith living room.
But the living room is changed. The furniture is stark and communist flags cover the walls. A Russian man with a gun chases them out of the house.
Out in the streets, a Soviet tank roars passed them. The ghost knows that Stan did something in the past and he changed the present. She makes him recap his trip to her. The ghost realizes that when Stan got Scorsese off drugs, he never made Taxi Driver and it changed a series of events that led to Walter Mondale getting into office and handing over America to the Soviets. Stan knows that he has to go back in time and make Taxi Driver.
Stan, Francine and the ghost return to 1974.
In 1974, Roger make millions of dollars using Stan's lost tape to find the hits of the decade.
Stan directs Taxi Driver, but when DeNiro quits, Stan recasts him with John Wayne. Stan doesn't care because John Hinckley only cares about Jodie Foster.
The ghost, Stan and Francine follow Hinckley to the movies. Hinckley doesn't like the movie and doesn't care about Foster. The ghost knows there's only one thing left to do. The ghost takes them to 1981.
They wait outside the Hilton where Hinckley is supposed to shoot Reagan. But because of Stan's meddling, Hinckley won't be there and it's up to Stan to shoot Reagan.
Roger roller skates around a party. His business manager calls to tell him that his latest record release is a failure and Roger is broke.
Stan refuses to shoot Reagan. Francine tells him that if he doesn't shoot Reagan there will be no Christmas. Above that, the ghost explains that Stan might not even have a family, he may never meet Francine. Stan charges the press line, gun drawn...
...Francine sits up in bed. Stan runs to the window and asks a paperboy what day it is. The paperboy shouts back, "Christmas!" The family runs downstairs, happy that Stan fixed the past and that they can celebrate Christmas. Roger stumbles down, still drunk and ranting about how he created disco, but the family doesn't believe him.