It is Christmas day. The Christmas tree is stripped of decorations and the candles are burned out. Nora is worried that a letter might arrive from Krogstad, revealing her secret to Torvald. The Nurse enters, carrying a box of fancy dress clothes. Nora asks after the children. It is clear that she has deliberately been spending less time with them. She asks the Nurse if they would forget their mother if she went away. She asks too how the Nurse managed to send her own child away to be looked after by others. The Nurse replies that she had no choice: her baby was illegitimate, the father did not help, and she would not have been able to take her present job if she had a child to look after.
Mrs Linde arrives and repairs a Neapolitan fisher-girl's dress that Torvald wants Nora to wear to a party in the upstairs flat the following evening. She is going to dance the Tarantella. Nora tells Mrs Linde that Dr Rank is suffering from tuberculosis of the spine, and that he inherited the sickness from his dissolute father. It is implied that the father had syphilis, a venereal disease.
Mrs Linde expresses concern about Dr Rank's daily visits. She believes that he is unduly fond of Nora and that he is the one who lent her the money. Nora refutes her suspicion about the source of the money.
Nora hears Torvald returning and quickly hustles Mrs Linde into the next room on the grounds that he cannot bear to see dressmaking going on. Once again, she asks Torvald not to dismiss Krogstad. She claims she is afraid that he will slander Torvald. Torvald replies that she is thinking of her father, who was similarly slandered. But Torvald insists that he, unlike her father, has a reputation that is above suspicion. He has let it be known that he is dismissing Krogstad, and cannot let it be thought that he is changing his mind under the persuasion of his wife. His final reason for dismissing Krogstad is that while he might overlook his "moral failings," he fears that he will embarrass him in public by treating him familiarly (they were once close friends).
Nora is shocked at her husband's narrow-mindedness. Stung by her judgment of him, Torvald decides to settle the matter and sends a letter of dismissal to Krogstad with his final salary. Nora, panic-stricken, begs him to recall the letter, but he refuses, assuring her that he would take any troubles that arose on his own shoulders. He suggests that she go and practice her Tarantella dance.
Dr Rank arrives and reveals to Nora that he expects to die within a month. He does not wish to have Torvald in his sick-room, but will send Nora a card with a black cross on it when his death is imminent. Nora flirts with Dr Rank, showing him her silk stockings. She plays with the idea of asking him for the money to pay off Krogstad, but he reveals that he loves her, and she decides that she cannot now ask him.
The Maid enters with Krogstad's visiting card. Nora invents a story for Dr Rank that a new dress is being delivered and asks him to keep Torvald occupied, as he must not see it. Dr Rank leaves and Krogstad enters with a letter for Torvald, telling him about the loan to Nora and her forgery of her father's signature. He tells Nora that he does not intend to accuse her publicly, but to blackmail Torvald. He will keep her bond showing details of the loan, rather than returning it when the loan is paid off, as is customary. He will not be content with his old job back; he wants a promotion. He drops the letter into the glass-fronted letter box, to which only Torvald has the key.
Mrs Linde enters. Nora, in a state of terror, shows her the letter. Mrs Linde realizes that Krogstad loaned Nora the money. Nora still expects that Torvald will take the blame entirely onto himself, as he has promised, but she wishes Mrs Linde to know that she alone is responsible. Mrs Linde believes that it is best that Torvald knows the truth. But Nora insists that he must not find out. Mrs Linde leaves to talk to Krogstad.
Nora is desperate to prevent Torvald from reading the letter. She distracts him by insisting that he play the piano while she practices the Tarantella. She dances increasingly wildly, and he tries to slow her down. Dr Rank takes over the piano while Torvald gives her instructions, which she ignores. She begs Torvald to focus only on her and not to open any letter until after the party. He agrees.
Mrs Linde tells Nora that Krogstad has left town until the following evening, and that she has left a note for him. Left alone, Nora works out that she has just thirty-one hours to live. Torvald enters, asking for his "little skylark", and she rushes to his arms.
In the character of the Nurse, Ibsen further explores the role of women. Like Mrs Linde, the Nurse has had to sacrifice her own happiness in order to survive financially. She has had to send away her own child and look after other people's.
The theme of inherited degeneracy is taken up in Dr Rank's sickness, inherited from a sexually promiscuous father. As the Bible has it, the sins of the father are visited on the son. Rank says, ".in every single family, in one way or another, some such inexorable retribution is being exacted."
The lack of truth in Nora's marriage is made clear by Mrs Linde's remark that Dr Rank knew about her friendship with Nora, but Torvald had no idea who she was. This is because she talks more openly with Dr Rank, but avoids mentioning any of her old friends to Torvald as he wants her totally to himself. Dr Rank, for his part, refrains from talking of his imminent death to Torvald as Torvald feels disgust at anything ugly, but Dr Rank does tell Nora. However, Nora's limitations are made clear in her responses to Dr Rank when he talks to her of his death. Like a spoilt child who thinks only of herself, Nora tells him that he is being absurd, "And I wanted you so much to be in a really good humor." To some extent, Nora is a product of her upbringing, which, as she later says, consisted in being indulged and treated as a pretty plaything first by her father, then by her husband.
An indication that the Helmer marriage is unraveling is Torvald's refusal to adopt his usual indulgent fatherly role opposite Nora's "little squirrel" act, when she makes a last attempt to wheedle him into keeping Krogstad in his job. In a mood for plain speaking, he tells her the brutal truth: Nora asked him to give Mrs Linde a job, and he has given her Krogstad's. Nora is too fearful of his reaction to meet his truth with hers, and can only think up fanciful reasons why he should not anger Krogstad. It is worth remembering here that Krogstad's only weapon is a dose of the truth - but the Helmer marriage is too flimsy to withstand such an onslaught.
Torvald's character does not emerge from this act in a positive light. He comes across as unbearably smug when he insists that he, unlike Nora's father, has a public reputation that is above suspicion. He also appears superficial in his concern with appearances: he worries less about Krogstad's fate than what others would think if they believed his wife had influenced his decision to employ or sack him. It is hard to sympathize with Torvald's final reasoning on the subject, that though he is willing to overlook Krogstad's "moral failings," he fears that he will embarrass him in public by treating him as a friend.
The symbolism of Nora's Tarantella dance is developed. The Tarantella was a wild, passionate southern Italian dance. Torvald chooses Nora's dance costume (indeed, he had it made for her in Capri). The dress represents the erotic beauty that he prizes in her. He finds himself aroused by the sight of her wearing it to dance the wild, passionate Tarantella at the party. But it is significant that Torvald tells Nora to practice the Tarantella while he shuts himself away in his office, stressing her isolation within her marriage. Nora, for her part, persuades him to watch her practice the dance in order to prevent him opening Krogstad's letter, so she is also shutting him away from an awareness of the truth about their marriage. He tries to rein in her wildness with his instructions, but she ignores his comments and dances more wildly.
The interaction between Nora and Torvald regarding the Tarantella shows two people not so much drawing apart as careering towards a catastrophic impasse. Torvald's comment that she is dancing "as if her life depended on it" is ironic: the continuation of her life with Torvald does depend on her distracting him from the reality contained in the letter. Just as Torvald shuts himself away in his office, Nora keeps him from his letterbox - all in the name of protecting him from seeing and hearing what is really going on.