In this new episode of Sound Tracks presented by KQED, San Francisco -- host Marco Werman and reporters Mirissa Neff, Alexis Bloom and Arun Rath fan out across the country and around the globe to tell three musical stories. The first features Scottish folk singer Julie Fowlis, who sings the title track to the animated movie, "Brave," and is leading a revival of Gaelic culture in the Highlands. The second story follows African singer and human rights activist Youssou N'dour as he tries to run for president of his country, Senegal. And the third profiles jazz superstar Wynton Marsalis on the road in Chicago with his orchestra, spreading the gospel of jazz to a new generation. The show closes with a "global hit" performance by Of Monsters and Men, a young band from Iceland.