1570 in the Italian city of Ferrara, and the convent of Santa Caterina is filled with noble women who are married to Christ because they cannot find husbands on the outside.
Enter 16 year old Serafina, howling with rage and hormones and determined to escape. Her arrival disrupts the harmony and stability of the convent, as overseen by Madonna Chiara, an abbess as fluent in politics as she is in prayer. She assigns the novice into the care of Suora Zuana, the scholarly nun who runs the dispensary and treats all manner of sickness, from pestilence and melancholy to self-inflicted wounds.
As an unlikely relationship builds between the two women, others figures stand watching and waiting; most notably the novice mistress, Suora Umiliana, a crusader for God and ever stricter piety and the mysterious, decrepit Suora Magdalena, incarcerated in her cell with a history of ecstasy and visions.