Francisca de Luarca, the daughter of a silk grower, is a dreamer of fabulous dreams - dreams in which the work of her father's silkworms is woven into robes for kings, cloaks for queens and carpets for their palaces. In far-off France, Marie Louise de Bourbon, niece of Louis XIV, dances in slippers of Spanish silk and imagines her own enchanted future. The lives of these two women - born on the same day, unfold in tandem, almost touching, as their destinies are spun out in seventeenth-century Spain.

Francisca is consumed with passion for her lover, a Catholic priest; her obsession with him shapes her fate. Marie Louise, yoked by political expediency to the strange, impotent Carlos II of Spain, is blamed for the royal couple's childlessness, and forced to bear the consequences.

In an atmosphere of superstition, the Inquisition conducts its reign of terror, ruthlessly destroying innocent lives. In countless tunnels beneath the city of Madrid, the Grand Inquisitor and his hooded torturers exact confessions from victims, even as two young women develop secret lives dedicated to resistance, transcendence and love.