On Christmas Eve, Greg, a solitary and taciturn police officer, doesn't hesitate to leave his daughter behind to go on a mission. To teach him a lesson, Santa Claus decides to grant his daughter's wish: that her father looks like Richard Silestone, the good-natured and heavily indebted family man from the beloved Christmas movie she adores. While Greg is sent into this improbable world, Richard accidentally lands in the real world and both men realize they have no choice but to complete each other's missions to reclaim their respective lives.

Set between Paris and Rome’s Cinecitta’s Studios in the 1970s, a struggling writer seeks inspiration for his second novel, and falls in love with a famous movie star.