Adapted from the novel of the same name by writer José de Alencar, "O Guarani" tells a love story, in which young Cecília, daughter of a Portuguese nobleman, falls in love with Peri, an indigenous man of the Guarani ethnic group. For the two almost teenagers – Cecília is 16 years old and Peri is 18 years old –, it is the discovery of love in a pure form, which begins with friendship and transforms in a breathtaking way, defying the couple's ethnic and cultural differences. The opera also features in its story the dispute between the Aimoré and Guarani tribes. It also shows Spain's economic interest in the Portuguese colony in the figure of the adventurer Gonzales who, although interested in Cecília, has as his main objective to dominate everyone in order to explore indigenous lands.