I think this song is about the death of Laura Branigan. She had black hair and the "she was taken at the midnight hour" refers to the fact that she died in her sleep. The no one knows could refer to either the fact that no one had previously diagnosed the brain condition that she died of, or it could be that no one knows where she goes when she dies. The rest of the song seems to be about death in general.
I think this song is about the death of Laura Branigan. She had black hair and the "she was taken at the midnight hour" refers to the fact that she died in her sleep. The no one knows could refer to either the fact that no one had previously diagnosed the brain condition that she died of, or it could be that no one knows where she goes when she dies. The rest of the song seems to be about death in general.