Míster Danger allies himself with the much-feared and eponymous Doña Bárbara, a malevolent and powerful figure from whom the novel's title is derived.
Doña Bárbara's infamy stems from her reputation for amassing property in the Llanos through litigation, as well as for her alleged practice of black magic.
She and Míster Peligro manage to swindle lands out of unknowing llaneros' hands and their efforts represent the principal source of opposition to the novel's protagonist's mission to bring law and order to the llanos.
The novel's protagonist, Santos Luzardo, is a llanos-born lawyer from Caracas who returns to his native land on a short trip to assess his family's landholdings.
He ultimately takes it upon himself to rid the region of the pervasive influence of Míster Peligro and Doña Bárbara.