A huge store in Buenos Aires is about to close due to restrictions on imports. The owner of the store returns from a vacation in France, and knowing the financial situation proceeds to throw a big gala party. He hires a man he had met abroad to pose as a fake earl, hoping to attract wealthy clients.
A handsome newcomer in a village marries a local girl. A year or so later an abandoned baby is left on the couple's doorstep, a baby the man had with another woman. They decide to raise the kid along with the one they had together.
Based on the career of Juan Manuel Fangio, an Argentine motorist who, in his first season in Formula 1, in 1950, achieved the runner-up; and that then between 1951 and 1958 he would obtain five world titles in Formula 1, driving with Mercedes Benz, Maserati, Alfa Romeo and Ferrari.
The plot reflects the figure of Pascual Contursi, tango poet. In love with a singer, he leaves his wife and son to go with her. Some time later, the singer leaves him and he composes the tango that gives the film its title.
It takes place in 1827, in Carmen de Patagones, in the context of the confrontation between the militias of the United Provinces of the Río de la Plata and the navy troops of the Empire of Brazil. It is the story of a fort lieutenant who falls in love with a young woman.