On the Kentucky frontier in 1821, Catholic nuns Mary Rhodes, Isabella Clark, and Helen Morton live in harmony in their vowed community. They belong to the Sisters of Loretto, and for almost a decade, these Sisters have educated young women on the frontier-including enslaved people and non-Catholics-with little help from the male authorities in their diocese. They have maintained the Loretto Order and their independence by adhering strictly to a life of sacrifice.

But when Father Nerinckx, the Sisters' longtime spiritual adviser, returns from Rome, he brings new papal edicts threatening the Loretto way of life. While Nerinckx opposes such commands, Father Chabrat, another local priest, wants to initiate them to exert control over the diocese and enforce the Sisters' obedience to the Church. Mary, Isabella, and Helen each face their struggles against patriarchal influence. Mary's desire to keep control and Isabella's naïve zeal clash with Chabrat's power grabs, while Helen burns with frustration from her futile efforts to achieve equity for her enslaved students. Can their faith quench the fire of disobedience glowing within them, or will these women scorch the past to forge an uncertain future?