在这部圣诞老人剧情/喜剧/家庭/奇幻片中,斯科特（蒂姆·艾伦 Tim Allen 饰）拥有一段失败的婚姻，离婚之后，儿子查理（艾力克·洛伊德 Eric Lloyd 饰）跟着母亲劳拉（温迪·古逊 Wendy Crewson 饰）生活。探视日很快就到了，斯科特兴致勃勃的准备去享受和儿子之间相处的短暂时光，但正当他准备出门之时，却发现有一个人在他家的屋顶上鬼鬼祟祟的不知道干着什么。斯科特一声大喝吓得屋顶上的人跌落下来，这时斯科特才震惊的发现，这个人居然是圣诞老人。
斯科特令圣诞老人无法工作，为了赎罪，他只能代替他成为新的圣诞老人，就这样，和查理一起，斯科特来到了圣诞老人的大本营，在这里，斯科特必须学习如何成为一名合格的圣诞老人。
Divorcee Scott Calvin is disgusted to learn that his ex and her husband have tried - and failed - to break it easy to their 6-year-old son Charlie that Santa isn't real. On Christmas Eve, Scott reads The Night Before Christmas... then receives an unexpected visitor on his roof. When he's startled by Scott's calling out and falls, the Santa impersonator disappears, leaving only an 8-reindeer sleigh and a suit with instructions to put it on if he's involved in an accident. Scott does, and is transported around the town dropping gifts through chimneys until he's taken to the North Pole and informed by a group who claim they're elves that he is now Santa. Charlie is proud of his dad's new job, though Scott's convinced it's a dream. Until his hair turns white, his beard refuses to stay shaved, he gains weight inexplicably, even for his sudden love of junk food... Now he's accepted it, there's just one problem: how to keep it secret from his disbelieving family?
