Holly is encouraged by her boss to take Christmas off. She goes home to her father, who runs a department store in her hometown. A crisis in the staffing of the Santa station in the department store means that they hire Nick, who is friends with the Santa renting company, and Holly herself jumps into Santa's helper.
It goes well with many of the common ingredients. The nod to the Cinderella story and the hunt for someone who fits the shoe (which actually doesn't take up much space in the film despite the title) gets silly, but if you ignore that, it's good.