In a country house near Padua, Diego anxiously awaits news of his wife Lavinia, who has been accused of attempting to poison him. Lavinia is declared innocent and returns to the house, where she is confronted by Diego and his family. Although Diego believes his wife to be guilty, he is taken in by Lavinia 's seductive charm and is overjoyed with the court's decision. His mother Emma insists upon an appearance of harmony among the members of the family, but his sister Zita cannot disguise her hatred of Lavinia.
Diego's brother Claudio, a priest, meets Lavinia in her bedroom at night. The two have felt emotionally bound to each other for some time, and now Lavinia, in a passionate outburst, declares her love for Claudio, who rushes from the house. The next morning all the members of the family are assembled again. Zita's taunting remarks and Claudio's confession of jealousy toward Diego and of self-righteousness undermine the semblance of family unity. Lavinia rejects any compromise and jumps to her death from her balcony. Diego flees the house, never to return.