During the so-called Conquest of the Desert, Major Sarabia is sent to the Cruz del Sur fort to replace Major Molina, who was murdered at the hands of the Indians. He is the only one who can stop Santiago, "the most rebellious of the caciques of the southern border, the only one who does not accept peace with the government."

During a conversation between a grandfather and his grandson, the latter tells him the story of the liberator General José de San Martín (1778-1850) from the patriot's childhood, through his stay in Spain, his return to the Río de la Plata, the development of the continental plan and the European exile.

The struggle to succeed and a love story of some Argentines who live in the Montparnasse neighborhood in Paris.