Lorenzo arrives back in Madrid with a representative of the Inquisition. During the procession honoring St. Clare, the prioress is arrested. Mother St. Ursula publicly relates the account of Agnes’s trial by the sisters. The majority voted for the most extreme punishment, which would entail Agnes being thrown in a dungeon and left for dead. However, at Mother St. Ursula’s instigation, the punishment is mitigated to death by poison. Agnes is then forced to drink the potion, which causes her to expire.
At Mother St. Ursula’s revelation that the prioress is a murderer, the crowd turns to rioting. Despite the Inquisitor’s pleas, she is attacked and killed by the crowd. Then they turn on the other nuns, vowing that all of them must be destroyed and the convent torn down.
In the confusion, Lorenzo finds a group of nuns and a young woman named Virginia hiding in the cemetery vault near the statue of St. Clare. Groans coming from the statue arouse Lorenzo’s suspicions. He manages to move the statue to find a passage leading down into a dungeon, where he finds Agnes, alive and holding the body of her baby. Lorenzo removes Agnes from the dungeon and with Virginia’s help, takes the group of nuns to safety.