The narrative returns to Don Lorenzo and Don Raymond, both grief-stricken and suspicious of the Prioress of St. Clare’s tale of Agnes’s death in childbirth. Don Lorenzo’s valet, Theodore, disguises himself as a beggar and street musician in order to insinuate himself with the nuns of St. Clare and gain more information about Agnes’s death. Delighted by his beauty and musical talent, the nuns invite Theodore into the abbey to perform. Hoping Agnes will hear his voice, he sings a ballad about a young woman tricked into marrying a “water-sprite” who drowns her. After his performance, one of the most respected of the nuns, Mother St. Ursula, slips Theodore a letter. Mother St. Ursula recognized Theodore as the servant of Agnes’s brother, Don Lorenzo, and the note informs Don Lorenzo that he must obtain an order of arrest for the Prioress of St. Clare and present it at the Festival of St. Clare. Mother St. Ursula promises to reveal the prioress’s crimes.

That night, Ambrosio employs the magic myrtle branch to enter Antonia’s home and bedchamber.