Cold, gray morning light illuminates the stage, and Hialmar has not returned. Dr. Relling informs them he is asleep on the sofa in his apartment. "How can he sleep?" asks the despairing Hedvig, and Gregers answers that the man needs rest after "the spiritual conflict which has rent him." Relling differs, observing that he noticed no such tumult in Hialmar. When Gina and Hedvig are out of the room, Gregers says he is amazed that Relling cannot see the greatness of Hialmar Ekdal's character. Raised by hysterical maiden aunts, replies the physician, Hialmar only passed as a great man. His father "who has been an ass all his days" approved of everything the young man did. The doctor continues:
But then when our dear sweet Hialmar went to college he at once passed for the great light of the future amongst his comrades too! He was handsome, the rascal — red and white — a shop girl's dream of manly beauty; and with his superficially emotional temperament and his sympathetic voice for declaiming other people's verses and other people's thoughts — [Here Gregers interrupts angrily.]
The physician begins to diagnose young Werle. "You, who are always in a delirium of hero worship," are sick. You must always have something outside yourself to adore, and Gregers admits the truth of Relling's observations. Relling tells young Werle that in Hialmar's case of sickness he applies the "usual remedy": "I am cultivating the life illusion in him," says the physician. As for Molvik, "since the harmless creature would have succumbed to self-contempt and despair" long ago, Relling, by way of cure, invented his being "demonic." Old Ekdal has found his own remedy, for "there is not a happier sportsman in the world than that old man pottering about" in the garret. Gregers agrees that the unfortunate old man has "indeed had to narrow the ideals of his youth." Don't use that foreign word "ideals," Relling retorts. "We have the excellent native word: "lies." Gregers vows to rest only after he has freed Hialmar from the doctor's clutches. "Rob the average man of his life illusion and you rob him of his happiness at the same stroke," warns Relling before he goes. With a final word to Hedvig to remind her that the "fearless spirit of sacrifice" would recall her father, Gregers also exits.
"How would you go about shooting a duck, grandfather?" the child asks as Lieutenant Ekdal emerges from the garret. In the breast, against the feathers, he answers, and retires into his room. Hedvig gingerly takes the double-barreled pistol from the shelf, hastily replacing it when Gina enters. Her mother bids her prepare a breakfast tray for father; suddenly Hialmar appears, bleary-eyed and disheveled. The child cries out for joy, but he turns away, telling Gina, "Keep her away from me, I say." Hedvig disappears without a word.
Hialmar asks his wife to pack his clothes for he intends to leave and "my helpless father will come with me." Searching for his papers in Hedvig's room, he cruelly orders her out. In my last moments in this my former home, Ekdal tells Gina, "I wish to be spared from interlopers." Hedvig stands alone onstage, fighting back her tears. Thinking of the wild duck, she takes the pistol and softly steals into the garret.
Meanwhile Hialmar, complaining about "the exhausting preparations" for leaving, sits down to his coffee, munching on heavily buttered bread. As Gina points out how difficult it will be to find accommodations for the birds and pigeons which his father needs, Hialmar decides to stay at home for a day or so until an available apartment turns up. He also decides to save the letter from Werle; he says it really belongs to father and he had no right to tear it up. Gregers enters at this point to find Hialmar gluing the torn pieces of paper together. He is disappointed to find Ekdal ready to leave the house and reminds him of the invention he must finish. There is no invention, answers Hialmar bitterly; it was all Relling's idea, and he continued to think of it because it made Hedvig so happy. "How unutterably I loved the child," moans the father, and now I begin to doubt that perhaps she has never honestly loved me. Hearing the duck quacking in the garret, Hialmar believes his father is hunting in there, but Gregar's face shows joy as he says that Hialmar may yet have proof of Hedvig's love. Continuing his dark thoughts, Ekdal asserts that, since she faces a rich future, the wealth will turn her head and Hedvig will surely leave him:
If I then asked her [he goes on], 'Hedvig, are you willing to renounce that life for me?' . . . you would soon hear what answer I should get.
A pistol shot rings out from the garret. Gina rushes in, worried that the old man is shooting by himself. Excitedly Gregers explains that Hedvig had her grandfather shoot the bird for if she sacrificed her most cherished possession "then you would surely come to love her again." When old Ekdal looks out from his room, they have a sudden foreboding, and rush into the garret. Hialmar and Gregers carry Hedvig to the sofa, and Relling, having come when called, pronounces her dead. Gina sobs and reaches for her husband. "We must help each other to bear it, for now she belongs to us both," she says.
Relling gazes searchingly at Gregers; the death was no accident, he declares accusingly. "Hedvig has not died in vain," young Werle asserts. "Did you not see how sorrow set free what was noble in Hialmar?" That is only temporary, answers the doctor. Within a year, Hedvig "will be nothing to him but a pretty theme for declamation." Hialmar shall soon steep himself in a "syrup of sentiment and self-admiration and self-pity," Relling tells the shocked Gregers. If you are right, then life is not worth living, the young man tells him:
Life would be quite tolerable after all [says the physician] if only we could get rid of the confounded duns that keep pestering us in our poverty with the claims of the ideal.
In that case, says Gregers as he prepares to go, I am glad for my destiny — "to be thirteenth at table." "The devil it is," mutters Relling as the curtain rings down.
Life would be quite tolerable, Relling says as he expresses the keynote of the play, if imperfect souls do not destroy themselves by trying to meet the claims of the ideal. Unable to accept this doctrine as an acceptable standard of life, Gregers chooses to be "thirteenth at table" — to remain outside the circle of the normal human condition. Hialmar, on the other hand, lacking personal integrity, will survive because he can easily build up a new series of self-deceptions to overcome temporary disillusion. He and Gina will continue their life together, sustaining their sense of personal worth with fresh fantasies.