Set during the Inquisition, Catherine, queen of Montalcino, rescues Isabella from a brutal rape. While convalescing, the women fall in love, creating a spiritual struggle for Catherine. Eventually, Catherine gives in to her love, marrying to cover the relationship. This intensifies the danger. The Bishop is determined to expose her. His own life a web of lies and secrecy, he seduces Catherine's naïve daughter, Sofia, into friendship. Sofia plays out the Bishop's intentions, propelling everyone toward disaster.