IMPOSSIBLE SAINTS alternates chapters between the narrative of the life of the fictional Saint Josephine and her secretly written biographies of a few chosen female saints. Josephine is a sixteenth century, upper-class, Spanish woman who chooses to become a nun at the age of sixteen against the wishes of her family. Her story starts when she is a child. Details are given of her relationship with her docile mother who dies very young and of her confused relationship with her father. The reasons she becomes a nun are her misconstrued love for her father and to find a modicum of freedom. She knows she would have none in marriage. She gains a reputation as a nun for her visions of Christ, but her visions are questioned as heretical by the inspectors of the inquisition. The threat of torture by the inspectors incites her to write her biography as well as tame biographies of female saints. She becomes the guardian of her young niece and raises her in the convent, but as both Josephine and Isabel grow they become restless in there. Josephine visits her cousin Magdelena and discovers a whole new world of sexual spirituality. She defines her own form of worship and founds a convent in order to forward her ideas.
The alternating chapters of the novel tell the story, in a purely secular way, of eleven female saints. Each saint is taken off of her holy pedestal and her conflict is told in terms of male oppression (or exploration) of her sexuality. These stories are interesting due to their earthly point-of-view, though the recurring theme of incestuous father-daughter love becomes uninteresting before the book is concluded.