Well, without more context, it's hard to define the specific 'you gonna cry christmas story'. Maybe it's a story where a poor child experiences a magical Christmas and the kindness of strangers, which is so moving that it brings tears. It might show the true spirit of Christmas and how it can change lives.
If it's a self - made or less - known 'you gonna cry christmas story', it might have unique elements. For example, it could be centered around an old Christmas tradition in a small town that was almost lost, and the efforts to revive it. This could involve the emotions of the older generation seeing it come back and the younger generation learning about their heritage, which could be a very emotional and potentially tear - inducing story.