Princess Stacy Wyndham of Belgravia and Queen Margaret Delacourt of Montenaro are preparing to host an international Christmas festival in Montenaro, the centerpiece of which is the "Star of Peace", a sacred relic loaned by the Vatican. Shortly after the Star arrives, thieves break into the palace and steal it. Stacy and Margaret decide to approach Lady Fiona Pembroke, who is currently on probation and working as a custodian at an orphanage, for help to track down the Star. She agrees to help in exchange for Margaret putting in a good word for her when her case is reviewed by a disciplinary board after Christmas. Fiona consults her ex-boyfriend, Peter Maxwell, a disgraced former
Interpol investigator who now runs his own private security firm. Peter quickly deduces that the mastermind behind the Star's disappearance is Hunter Cunard, a billionaire obsessed with stealing priceless works of art for his personal collection. Fiona charms Hunter into giving her an invitation to the Christmas party at his estate. Peter then recruits Fiona's assistants, Mindy and Reggie, to practice infiltrating Hunter's estate and bypassing his security measures while Fiona distracts him at the party. Reggie injures himself during training, so Margaret agrees to impersonate Fiona at the party. This is while Peter and Fiona, stepping in for Reggie, retrieve the Star from the security vault. As they get ready for the mission, Fiona reflects over her unrequited feelings for Peter, whom she has known since childhood. The plan is set into motion, and at first, everything goes smoothly until Peter accidentally trips a pressure plate alarm while retrieving the Star. Panicked, Reggie and Mindy shut off the fake security footage Peter had installed, alerting Hunter to the theft. Peter gives Fiona a bag with the Star and stays behind to distract Hunter's men while Frank picks up Fiona. Margaret also escapes with the help of the coat check angel man. Meanwhile, Stacy receives word from the head of the orphanage that Fiona's hearing has been rescheduled to the same night as the heist. She decides to dress up as Fiona and appear in front of the committee, accompanied by Prince Edward as a character witness. With Stacy impersonating a remorseful Fiona, the board decides on a commutation of sentence. Everyone regroups at the palace, but Fiona soon discovers that the bag she is carrying contains a decoy. Believing that Peter tricked them, Margaret and Stacy agree to reveal the truth to the Vatican. However, Fiona, Mindy, and Reggie plan to leave the county despite Margaret inviting them to stay for Christmas. Peter asks Fiona to meet him, and when she does he explains that he took the Star to get her attention. He asks her to speak with Bianca, who has traveled to Montenaro to make peace with her daughter. Fiona angrily refuses to forgive her and is about to leave when she realizes that doing so would be repeating the same mistake her mother made. She goes back and hugs Bianca, forgiving her. They then return the Star to Stacy and Margaret just in time. At the lighting of the festival's Christmas tree, Margaret reveals to Kevin that she gave the police evidence of Hunter's crimes. Fiona, despite finally being welcomed back into her cousin's family, is miserable about not having anyone to share the holiday with when Peter suddenly reappears despite their fight. They share a kiss as the Star of Peace lights up to celebrate the
new year. ==Cast==