Antonio is the husband of a rich heiress who, shortly before his wife's death, realizing he risks being expelled from the estate, convinces the dying woman to ask their small daughter Rosa for a vow of chastity, so that she cannot marry until the death of father. Twenty years later, she is now a beautiful woman, all home and church, who lives in respect of the oath made on her mother's deathbed. Soon, however, she starts first to have strange dreams and then to have winking night visits from her cousin Fernando. Extremely disturbed by these events, she confides to her confessor pastor that she wants to become a nun and to give all her belongings to charity. As soon as his father becomes aware of this idea, in order not to lose the patrimony of which he is the usufructuary, he organizes a group sexual initiation towards his daughter. This event, however, opens the eyes of Rosa who finally makes herself independent.