The Goretti and Serenelli families live in the same house and work in the service of Count Mazzoleni. Just like all the other peasants who work with them in the Pontine Marshes at the beginning of the 20th century, the risk of contracting malaria is extremely high.
Such are the social tensions of the time that the people start to seek justice. Some become venomous in their ferocious response to their sufferings. This is context in which the two children grow up. Until Alessandro finds his views differing from those of Maria to the point that he kills Maria with his knife. As she dies, the young girl, a faithful Christian, forgives Alessandro, showing that hatred can be answered with love.