The beautiful Beatrice Cenci, daughter of the noble Francesco, falls in love with Olimpio. But she has to face the jealousy of his violent and morbid father, and the hostility of his stepmother Lucrezia, who has a relationship with her other stepson, James. The stepmother and stepson-lover plan to kill Francesco. And when the latter dies accidentally, they decide to put the blame on Beatrice and Olimpio.