The American woman in question is Jules Daly (played by Katie McGrath), who is struggling to make ends meet as a housekeeper in Buffalo, New York. She is a single woman in her thirties, who is determined to look after her niece and nephew, Maddie and Milo, after their parents die in a car accident.
Meanwhile, in Europe, Prince Ashton (played by Sam Heughan) is struggling to find a suitable wife. His parents, the King and Queen of Castlebury, want him to settle down and have children. However, Prince Ashton is not interested in any of the eligible ladies who attend his balls and soirees.
One day, the Duke of Castlebury (played by Roger Moore) contacts Jules and invites her and her family to spend Christmas at the castle. Jules is taken aback by the invitation but decides to go, thinking it will be a once-in-a-lifetime opportunity for her niece and nephew.
When Jules and her family arrive at the castle, they are greeted by the staff, who are initially cold and unfriendly towards them. However, Jules makes a good impression on the Duke, who takes her under his wing. She is given a room in the castle and is made to feel welcome.
Prince Ashton and Jules meet at a children's Christmas party, where they bond over their love of sledging. Over the course of the movie, they grow closer and start to develop feelings for each other. However, both of them are hesitant to act on their feelings, as they come from very different worlds.
When Jules' ex-boyfriend shows up at the castle and causes trouble, Prince Ashton steps in to defend her. He and Jules share a kiss under the mistletoe, but are interrupted by the Duke, who disapproves of their relationship.
Will Jules and Prince Ashton overcome their differences and be together? You'll have to watch A Princess For Christmas to find out!