Almost fifty years ago, when she was very young and unknown, Mercedes Sosa broke the mould by drafting, together with other four young artists, the so-called "Manifesto del Nuevo Cancionero" (The New songbook Manifesto). How did this manifesto make an impact on the next generations? How much did the "Nuevo Cancionero" influence the development of the "Nueva Trova Cubana"? How did this ideology affect the politics of both emerging and developed countries? Apart from the millions of records she sold, the thousands of concerts she made all over the world, her countless fans and detractors, Mercedes Sosa left behind an indelible legacy, an ideal that has not become a reality yet but which keeps pushing forward. "Mercedes Sosa, The Voice of Latin America" is a deep intimate journey into Mercedes Sosa's world, not only as an artist but as human being. An autobiography through her own voice. She will guide us through her life, her successes and failures, her love stories and all her suffering. With never seen before achieve, an artistic construction and several international artists giving their testimony about Mercedes Sosa's importance for Latin America political and musical history, this documentary will show the ideology of an artists who went beyond the borders of music , to become in one of the most influential personalities of the 20th century.