Having seen that the antidote was taking good effect, Lucrezia hurried the still half-dazed Gennaro out of the palace through an unfrequented passage; and bidding him betake himself to Venice, she hoped he was safe from further harm.
Being no longer occupied with the engrossing pleasure of her newly-found son's society, and freed from the softening influence which he had exercised over her, Lucrezia became once more involved in her political schemes and personal intrigues; and having vowed vengeance upon the young Duke Orsini and his four companions for their denunciation of her to Gennaro, she proceeded to take her revenge upon them at a splendid banquet to be held at the palace of the Princess Negroni, a lady whose entertainments were always attended by the victims she had marked out.
When the night of the banquet arrived, the cunning Borgia managed to poison a flagon of rich wine, which she caused to be served out to the five nobles whose deaths she desired; and then she concealed herself, to await the consummation of her plan.
As the revels waxed more boisterous, Orsini, exhilarated by the rare wine he had been served with, entertained the company by singing a gay drinking song; and amidst the applause which followed his performance, Lucrezia made her appearance, and revealing herself to Orsini and his companions, announced with cruel triumph that they had all partaken of poisoned wine and that in a few minutes they would be dead. At her command, the attendants showed the five victims the coffins in which they would shortly lie; but at this moment, when her vengeance was just consummated, she was suddenly prostrated with horror. For Gennaro, who, neglectful of her bidding, had remained in Ferrara, now suddenly appeared before her; and, announcing that he also, as a guest at the banquet, had partaken of the poisoned wine, sternly desired her to provide a sixth coffin for his remains when he should presently breathe his last.
The revellers, overcome by this tragic interruption to their mirth, left the banqueting hall one by one, with pale faces and trembling steps; and the mother and son were left alone.
Lucrezia was filled with the utmost horror on thus discovering that she had once again caused her beloved son to be poisoned; and quickly producing the antidote, with tears and entreaties she begged him to swallow it instantly, her anxiety at his extreme danger being so great that, unable to control her feelings, she now revealed herself to him as his mother.
But Gennaro refused to accept the antidote; for he was stunned by the announcement that this terrible woman, whose cold-blooded murder of his friends repelled him with horror, was his mother. It was in vain that Lucrezia, seeing that the poison was already taking deadly effect upon her gasping son, entreated him passionately to take the antidote which she offered to him, and which alone could save his life; for Gennaro was determined not to live since his friends were doomed to die, and, regardless of his mother's despair, he thrust the antidote aside, and a few moments later fell back in her arms, dead.
At this moment, the Duke Alphonso entered the room; and Lucrezia, in a paroxysm of grief and wild despair, revealed to him the true relationship in which she had stood to Gennaro.
The Duke had scarcely time to grasp the meaning of her distracted words, when the wretched Lucrezia herself fell gasping to the floor; for the shock of having unwittingly murdered her own son was greater than she had strength to bear, and with a last despairing cry of woe and remorse, she fell dead beside the still form of her beloved Gennaro.