Well, without more context, 'big black story' could mean a lot of things. It might refer to a significant or mysterious story that has some connection to the color black, perhaps symbolically. For example, it could be a story about a black - themed event, a character in a story who is black and has a major role, or it could be something as simple as a story that is 'big' and has a dark or serious undertone.
It's really hard to say exactly what 'big black story' means just from that phrase. 'Big' could imply importance or magnitude, and 'black' could have various connotations. It could be a cultural reference, like a story from a particular black community or about black history. Maybe it's a story someone made up that involves a big, black object or creature. There are so many possibilities.
The 'big black story' could potentially be a very personal or local story. 'Big' might suggest that it has a lot of details or a wide - reaching impact within a certain group. 'Black' might not be referring to the color literally but could be associated with something negative, like a difficult or sad story. It could also be a creative or fictional story someone created where 'big' and 'black' are used in a more abstract way to set the mood or theme of the story.