Viridiana (Silvia Pinal) is on the verge of completing her vows as a nun when her uncle, who is obsessed with her, incorrectly leads her to believe that she has been defiled by him in her sleep. When the uncle takes his own life and bequeaths his grand estate to her, Viridiana abandons nunhood and attempts to repent and lead a morally pure existence by turning the mansion into a shelter for vagrants.