Well, without more context, it's difficult to say precisely. It might be a story centered around a black cross as an object. Maybe it's a mystery story where the black cross holds a key to solving a case, or it could be a story set in a religious or superstitious context where the black cross has special significance.
I'm not sure specifically as I don't know which 'the black cross story' you're referring to. It could be about a lot of things, like a historical event related to a black cross, or a fictional story where the black cross has some symbolic meaning.