Marge and Homer's plans for a romantic date night fall through when Homer is forced to stay longer than expected at the Springfield Nuclear Power Plant to fix a leak in one of the plant's nuclear processing pipes. Looking for a romantic activity after walking out of a movie starring Ben Affleck, they find an ice rink and decide to do some skating. However, they are unable to rent skates because it is curling night. They decide to try it and discover their innate talent for the sport — particularly Marge, who has years of experience sweeping floors. Agnes and Seymour Skinner notice and invite Marge and Homer to join their mixed-doubles team. It is announced that mixed-doubles has been added to the Winter Olympics as a demonstration sport, and the Skinner-Simpson team qualifies for the United States curling trials. Agnes cautions Marge not to let emotions get in the way of winning, relating how a fetal kick by an unborn Seymour foiled her chances at winning gold in pole vault at the 1952 Summer Olympics in Helsinki. At the trials, Marge's talented sweeping earns the team a win and a trip to the Winter Olympics in Vancouver.
Meanwhile, at the trials, Lisa is given an Olympic mascot pin. Lisa puts it on her shirt and decides it "looks lonely" and buys another, but her interest in them quickly spirals out of control. The Simpsons arrive in Vancouver, where Agnes insists that Homer be cut from the team. Marge insists she can compensate for his weak throws, but she injures her right shoulder while sweeping to secure a win in the semifinals. She is told that she will never curl again and that the American team must forfeit the gold-medal match to Sweden. Lisa's pin collection grows, and when she runs out of money, she trades her pearl necklace to a vendor in exchange for a pin from the 1924 Winter Olympics in Chamonix, France. Bart discovers Lisa busking on a street corner, having relinquished her dress in favour of wearing her pins at all times, and offers to help her kick her pin-collecting addiction. Cutting the lower portion of Homer's face from his driver's license and making it into a pin, Bart creates "Fatov", a phony mascot for the 2014 Winter Olympics in Sochi, Russia. He trades the pin to the vendor in exchange for Lisa's necklace.
As Marge prepares to leave Vancouver, she reveals to Homer that she is left-handed, but has always used her right hand to avoid seeming unusual (due to years of using her right hand, it renders her cross-dominant). She has enough dexterity to change Maggie's diaper and dress her one-handed. They return to the rink just in time to stop Seymour from forfeiting the match and go on to defeat Sweden for the gold. Agnes softens her attitude of unyielding contempt toward her son after he breaks his broom and has to drop out, and Marge and Homer agree that they had a great date night.