Mexican rancher Emiliano Zapata (Marlon Brando) becomes a revolutionary when corrupt President Porfirio Diaz (Fay Roope) ignores the needs of his people. Zapata, his brother Eufemio (Anthony Quinn) and northern rebel Pancho Villa (Alan Reed) band together behind Diaz's political opponent, Francisco Madero (Harold Gordon). But when Madero's administration, particularly General Victoriano Huerta (Frank Silvera), proves just as corrupt as the one it replaced, Zapata is spurred to further action.