Hip-hop music first developed in the United States in the 1970s and has steadily grown in popularity in the decades since then. This docuseries traces the genre's dynamic evolution from the beginning through the 1990s. It starts with a look at artists -- including Afrika Bambaataa and Grandmaster Flash -- who laid the foundation early on, and then moves on to other influential groups like Run-DMC and Public Enemy. The show also explores differences in hip-hop on the East Coast compared to the West Coast.