Arriving in 19th-century Madrid, the beautiful Isidora Rufete clings to the mistaken, passionate belief that she is a marquesa’s illegitimate granddaughter. Driven by the dream of inherited nobility, she attempts to claim her rightful place in high society. As her desperate efforts to live a life of luxury and love crumble under the harsh reality of her true, poor origins, Isidora’s fateful trajectory becomes a devastating naturalist study of ambition, self-deception, and the calamitous consequences of social climbing in a rigid, unforgiving world, leading her to prostitution and the prison cell.