Watch A Princess for Christmas for Free: How to Stream the Movie Online at 123Movies. . After her sister and brother-in-law's tragic deaths, an American woman who is the guardian for her young niece and nephew is invited to a royal European castle for Christmas by her late brother-in-law's father, the Duke of Castlebury. Feeling out of place as a commoner, she is determined to give her family a merry Christmas and surprises herself when she falls for a handsome prince.