A young man named Giovanni rents a room in an old edifice belonging to a family whose ancestor was listed among the sufferers in Dante’s Inferno. It looks down on a luxuriant inner garden belonging to a neighbor, Dr. Rappaccini. The garden is brilliant with exotic blooms, the most spectacular a shrub growing by a ruined fountain. It is covered with rich purple blossoms. Dr. Rappaccini often tends the garden, but he is always protected by heavy gloves and sometimes a face mask. His lovely daughter, Beatrice, takes no such precautions, however, and she is the only one who touches the handsome plant with the purple blooms. She tends it as though it were a beloved sister.

Giovanni has a letter of introduction to a Dr. Pietro Baglioni, a professor of medicine at the university, who once knew his father. Dr. Baglioni warns him to keep away from Rappaccini, a brilliant scientist but one inclined to sacrifice anything and anyone to his scientific experiments. He is an expert in poisons and is known to have developed new varieties of herbs more poisonous than those in nature.

Such information lends substance to Giovanni’s lurid imaginings about the garden and the girl. He had once thrown her a bouquet that had seemed to wilt the moment she picked it up. He also fancied that a butterfly that hovered close to her face had died suddenly in mid-flight.

These forebodings do not prevent him from entering the garden when his landlady, Lisabetta, offers to show him a secret door into the inner courtyard. Beatrice comes out to meet him, and they are drawn to each other immediately. When he asks for a blossom from the shrub at the ruined fountain and reaches out to pluck it, Beatrice cries out in alarm, seizes his hand, and warns him never to touch it. The next morning, the place where she grasped his hand is painful and inflamed.

Giovanni continues to visit Beatrice, until he notices with horror that flowers will no longer remain fresh in his own hands. As an experiment, he exhales a long breath on a spider that is industriously weaving a web in his room: the spider curls up and dies immediately. Tortured now by fear and resentment, Giovanni paces the streets of Padua, where Dr. Baglioni sees him and divines the reason for his distraction. Dr. Baglioni brings him a silver vial containing an antidote that was originally created to counteract the poisons of the Borgias. He instructs Giovanni to give the antidote to Beatrice to counteract the deadly fumes in which she has lived.

When Beatrice again calls from the garden, he goes down to her with hatred and resentment in his heart, instead of love. He curses her for contaminating him with her poison. Beatrice is crushed by his cruel words, having always assumed that he was safe so long as he did not touch her or the flowers. He accuses her of deliberately trapping him to share in her isolation from the world. This she passionately denies: “I dreamed only to love thee and be with thee a little time, and so let thee pass away. . . . For Giovanni, believe it, though my body be nourished with poison, my spirit is God’s creature and craves love as its daily food.”

Giovanni is somewhat mollified and tells her of the antidote that Dr. Baglioni provided. Perhaps they can both escape the garden. Beatrice agrees but adds emphatically, “I will drink; but do thou wait the result.” She does so and dies at the feet of Giovanni...