"Johnny Cash was an American icon, known for his level bass-baritone voice and somber demeanor, for huge hits like 'Ring of Fire' and 'I Walk the Line.' He's one of the best-selling musicians of all time, and his crossover appeal earned him inductions into the Country Music, Gospel Music, and Rock and Roll Halls of Fame. But he was also the most prominent political artist in the United States, even if he wasn't recognized for it in his own lifetime,...

It tells the tale of the musical Carter and Cash Family, the dynasty at the heart of country music. Starting with the Original Carter Family, A.P., Sara and Maybelle, this film traces the flow of their influence through generations of musicians, the transformation of that act into the Carter Sisters and Mother Maybelle, the marriage of Johnny Cash and June Carter, and the efforts of the present-day family to keep this musical legacy alive.