Teresa de Cepeda y Ahumada (Paz) decides to enter the enclosed convent of the Incarnation, in which she discovers that still exist the materialism and frivolity she is trying to run from. So, she starts a crusade based on prayer and sacrifice but the ecclesiatical hierarchy believes she is possesed by the devil. Against the violence of the Church Teresa will find the help of the aristocratic Donna Guiomar and Friar Pedro de Alcantara, who both trust her and help her to discover her destiny.