Louisa loves Antonio. Her brother Ferdinand loves Clara. But Don Pedro and his second wife plan to place Clara in a convent, and Don Jerome, father of Ferdinand and Louisa, intends to force Louisa to marry odious Isaac Mendoza. Jerome has sworn not to see or speak to Louisa until she consents to the marriage. Margaret, the homely old duenna, agrees to help Louisa elope if Louisa will resign Isaac to her, which plan Louisa is happy to consent to. To Ferdinand, Jerome confesses he married Ferdinand's mother for her money; thus he sees no reason why Louisa should not marry Isaac for his. Caught (as she intended) with an incriminating letter, Margaret confesses plotting to aid Louisa's elopement with Antonio, and Jerome dismisses her. This act enables Louisa to leave dressed as Margaret and undetected by Jerome. Meeting Clara, who has just run away from her father, Louisa asks and is granted permission to pretend to be Clara when she meets Isaac, who has never seen her. Happy to take the supposed Clara to meet Antonio, who once loved Clara and may fall again, Isaac leaves Louisa at his lodgings until he can visit Don Jerome and meet the beauteous Louisa. She warns him that he may find Louisa rather matronly. In Jerome's library he lists for Isaac his daughter's beauties-her sparkling eyes, her dimple, her lovely skin and voice of a nightingale-and sends him to woo her in her dressing room. Meeting the duenna, Isaac mutters, ". . . zounds this can never be Louisa-she's as old as my mother"; but when she mentions her father he concludes. ". . . 'tis well my affections are fixed on her fortune and not her person." DUENNASignor, wont you sit? She sits.]ISAACPardon me, madam, I have scarce recover'd my astonishment at-your condescension, madam-she has the devil's own dimples to be sure. Aside.]DUENNANay, you shall not stand he sits]. I do not wonder, Sir, that you are surpriz'd at my affability-I own Signor, that I was vastly preposessed against you, and being teiz'd by my father, I did give some encouragement to Antonio. But then, Sir, you were described to me as a quite different person.ISAACAye, and so you was to me upon my soul, madam.DUENNABut when I saw you, I was never more struck in my life.ISAACThat was just my case too, madam; I was struck all on a heap for my part.