Blues is a word you have to think about before it can be understood. Contrary to popular belief, blues - as a form of music - dies not appear until 1910 or so, that is after ragtime and jazz. Blues is not, therefore, the cornerstone of popular music. Rather, it has become an amotional response, through music, to a variety of oppressive social conditions. The episode begins in the delta of the Mississippi and follows the progress of itinerant blue smusicians to the steel mills and automobile factories of Chicago: from harmonica and fiddle, to electric guitar and fashionable nightclub. Finally, the episode shows how blues phrases and harmonies were stolen by white rock'n'rollers in need of a new gimmick.