In 1948 the partisan violence scars the Colombian countryside. Liberals and Conservatives learn to face up to death at every turn. In the South of the country at Tolima, Conservative official forces brutally kill several Liberal farmers, among them the husband of Rosalba Velasco. The young woman, who is the mother of a two year old child, witnesses the massacre and suffers a mental process of depersonalization and herself becomes an instrument of revenge and death. During one decade her actions will leave an endless number of dead police and civilians and she becomes a target for the army, the police and the paramilitary bands of the time.
The leaders of the Liberal illegal armed bands, opposed to the Conservative Government, try to neutralize Rosalba's excesses and recruit her as a militant. The young woman stands out for her courage and gains the respect and admiration of her male companions. She becomes known by the alias "Sargento Matacho" and is soon a legendary figure among the Colombian guerrilla movement. Though an emotionally disturbed woman, she generates an inevitable aura of attraction but her life becomes a paradox as she gives birth to several children while killing so many people herself. She eventually dies at hands of the Colombian army when she is on the verge of giving birth to a son fathered by Desquite, a famous brigand of the time.