The plot tells the story of Sinhá Moça, daughter of the powerful Colonel Ferreira, the slave owner Baron of Araruna, and Cândida. A dreamer and a romantic, Sinhá Moça falls in love with Rodolfo, an active abolitionist republican. She meets the young man on the train, when she travels back to Araruna after finishing her studies in the capital of the province. Like Rodolfo, Sinhá Moça has abolitionist ideas and criticizes her father's actions, fighting in defense of black people. Together with Rodolfo and other young abolitionists, she fights for the liberation of slaves.