I'm not sure which specific 'Jack Black Christmas story' you mean. There could be various stories involving Jack Black related to Christmas. Maybe it's a story about Jack Black's Christmas adventures, like he could be trying to save Christmas in a comical way or having a wild Christmas party. Without more context, it's hard to tell the exact story.
Well, if we assume it's a story about Jack Black during Christmas, there might be elements such as a Christmas setting, like a snowy town or a big Christmas party. His character could be on a quest for something related to Christmas, like finding a rare Christmas present for a loved one. There may also be other characters, like Santa Claus or elves, that interact with him and help him along the way. And of course, the story would probably end with a happy Christmas conclusion.
Another theme is his relationships. Fanfictions might focus on his relationship with other main characters, like how he interacts with Jamie Fraser. This can range from adversarial relationships to more complex, unexpected connections.