Shows the unfailing love of two women for the same man, one as his mistress, the other as his wife. The lives of these characters intertwine and are determined by the variegated fabric of delicate tradition and established vices shaky politics and intrigue of the society they live in. Based on the major novel (1877) by Benito Perez Galdos.

Juan Santacruz, llamado "el Delfín", es el único hijo varón de la familia Santacruz. Le espera un brillante futuro, que incluye su boda con su prima Jacinta. Sin embargo, en su vida se cruza Fortunata, una apasionada mujer de clase baja de la que se enamora.