Stacy DeNovo is a talented young baker who runs a successful pastry shop in Chicago with her best friend Kevin Richards. Kevin has a daughter named Olivia, a precocious young girl who enjoys ballet dancing. Stacy has recently broken up with her boyfriend Paul. A week before Christmas, Stacy discovers that Kevin has entered their business in a prestigious baking competition in the Kingdom of Belgravia. Their submission was accepted, but Stacy is reluctant to attend, since Christmas is a uncomfortable reminder of her relationship with Paul. Later, Stacy runs into Paul with his new girlfriend. A kindly man on the street reminds her that Christmas wishes can come true. Stacy agrees to compete and leaves for Belgravia, along with Kevin and Olivia. Once arrived in Belgravia, the trio goes sightseeing and encounters a Christmas stocking seller who looks very similar to the kindly man Stacy met back in Chicago. The seller advises her to live life more spontaneously. After settling in at their cottage, Stacy and Kevin go to the television studio where the competition will be held. There, Stacy encounters her former culinary classmate and rival Brianna, the competition's defending champion. Brianna "accidentally" spills coffee on Stacy's apron, and Stacy leaves to get a new one. Then, Stacy meets Lady Margaret Delacourt, Duchess of Montenaro and fiancée of Crown Prince Edward of Belgravia, and the two are struck by their identical looks. Desperate for time out of the spotlight, Margaret suggests that the two switch places for two days, then switch back in time for Stacy's competition and Margaret and Edward's wedding. Initially reluctant, Stacy agrees, especially when Lady Margaret offers to sponsor Olivia as a student in Belgravia's acclaimed summer ballet program. Stacy and Margaret quickly teach each other about their lives, behaviors and quirks to minimize suspicion and part ways. Olivia immediately finds out about the switch, but helps to keep Margaret and Stacy's secret while bonding with Margaret. Meanwhile, Prince Edward - who was supposed to be away on business for the two days of the switch - changes his plans and wants to spend time with his fiancée, sending Stacy into a panic. King George senses something is afoot, and tasks his butler, Frank, to observe her. Stacy adapts to court life and begins to fall in love with Prince Edward, while Margaret falls in love with Kevin and realizes that she loves living a normal life. Despite this, both reunite and switch back after two days. Meanwhile, Brianna sneaks into the TV station and cuts off the power cord to Stacy's mixer as a sabotage. Frank the butler takes pictures to prove Margaret and Stacy swapped identities, and presents them to the Queen. The Queen encounters the same kindly man, who thinks Stacy looks like a princess despite her common status, and the Queen has a change of heart. Now aware of the switch, the Queen fakes illness to dispatch Edward and Margaret to attend the baking competition in her place. Margaret comes clean to Edward about the switch, and admits she does not love him. The two rush to the competition to resolve matters. At the baking competition, Stacy discovers Brianna's vandalism and has to mix her ingredients by hand. Despite the setback, Stacy and Kevin manage to complete their cake and win first prize, with medals presented by Lady Margaret and Prince Edward. Stacy tries to avoid the medal presentation, and Kevin - unaware of the switch - insists that she accepts. Margaret and Stacy reveal their plot to the two men. Margaret professes her love for Kevin, while Stacy walks away, feeling out of place in Edward's royal life. Edward stops Stacy and says he is in love with her. He proposes, suggesting a Christmas wedding in a year if they are still in love. One year later, Stacy marries Prince Edward and becomes Princess of Belgravia, and both couples (and Olivia) celebrate at the wedding. Margaret catches Stacy's bridal bouquet, while Kevin insinuates that he plans to propose.