Isaura was born in 1835, in the farm of Commender Almeida. She is the daughter of the slave Juliana and the tenant of the farm, Miguel. Juliana dies right after the birth, because she denied going to bed with the Commender. He whips her to death in revenge. So, Isaura is raised and educated by Gertrudes, wife of the Commender, who always wanted to have a daughter. In spite of her excellent education and the white skin, Isaura, as a daughter of a slave,will always be treated as a slave.
In 1854, Isaura is 19 years old and she is a beautiful maiden. Her problems begin when Leôncio, son of the Commender, enters her life and develops a sick passion for her, but all attemps are useless.
Gertrudes and Commender Almeida have always wanted to set Isaura free, but they die before doing so. Leôncio burns the document where freedom is granted to the girl and forces her to work as a slave. Besides all the suffering, Isaura still has to accept Leôncio’s rudeness and harassment.
Amidst all these problems, Isaura decides to flee with her father to a farm near São Paulo, using the name of Elvira, where she meets the young abolitionist Álvaro. Despite all efforts not to reveal her identity, Isaura is exposed and they take her back to the farm where she will have to face Leôncio and his vengeance. She also will face Branca, a rich woman, promised to marry Álvaro, who is in love with Isaura and does not want to get married.