Sparks fly during the holidays when Postman Matt meets his mysterious new coworker Kristi. As an official "Santa Writer, " Kristi is buried in children's letters to Santa. Her job: respond to every letter addressed to St. Nick. Their petty boss gets suspicious of this new employee that fell out of thin air, so he enlists a reluctant Matt to spy on her. But the more Matt gets to know Kristi, the more he falls in love.