From the opening of the act to the arrival of Krogstad’s second letter.
Mrs. Linde sits in the Helmers’ house, waiting. Krogstad soon appears in the doorway, having received a note from Mrs. Linde asking her to meet him. She tells him that they have “a great deal to talk about,” and it becomes apparent that Mrs. Linde once had romantic relations with Krogstad but broke them off in order to marry Mr. Linde, who had more money. Mrs. Linde says that she felt the marriage was necessary for the sake of her brothers and mother but regrets having ignored her heart, which told her to stay with Krogstad. She tells Krogstad that she wants to get back together with him, to take care of him and his children. Krogstad is overjoyed.
Mrs. Linde hears the music stop upstairs and realizes that Torvald and Nora will soon return. She tells Krogstad that his letter is still in Torvald’s letterbox, and Krogstad momentarily questions Mrs. Linde’s true motives—perhaps she has promised herself to him only to save Nora. Mrs. Linde calms Krogstad, saying “when you’ve sold yourself once for someone else, you never do it again.” She even tells him that although she originally hoped to persuade him to ask for his letter back, after observing the Helmer household, she feels that Torvald must discover the truth about Nora. The dance ends, and Mrs. Linde urges Krogstad to leave. He says that he will wait for her downstairs, and she suggests that he walk her home. Krogstad then exits.
Excited by the prospect of a new life, Mrs. Linde puts on her coat and prepares to leave. Nora and Torvald enter, Nora begging to return to the party. Torvald compliments and teases Nora for Mrs. Linde’s benefit, then leaves the room in search of a candle. While he is gone, Mrs. Linde tells Nora that she has spoken to Krogstad and that Nora must tell her husband everything. Nora says, “I knew,” but then says that she will not tell Torvald. Mrs. Linde reminds her of the letter. Torvald returns, notices Mrs. Linde’s knitting, and tells her that she should take up embroidery instead, saying that embroidery is a more graceful pastime than knitting. Mrs. Linde says goodnight and then departs.
Torvald expresses his relief that Nora’s boring friend has gone, and he begins to move toward his wife. She tells him to stop watching her, but he protests that he is always entitled to watch his “prize possession.” He continues his sexual advances, telling Nora that when they are in public, he imagines her as his “secret fiancée” and “young bride.” Nora continues to protest, saying she wishes to be alone.
Dr. Rank knocks on the door, annoying Torvald by calling so late. In front of Torvald, Nora and Dr. Rank speak in coded terms about the experiment that Dr. Rank was to do on himself; Dr. Rank says that the result is clear, then exits. Torvald thinks that Dr. Rank is simply drunk, but Nora understands that Dr. Rank has come to tell her that he is certain of his impending death.
Torvald goes to retrieve his mail and notices that someone has been tampering with the mailbox lock using one of Nora’s hairpins. Nora blames the children. In the mail, Torvald finds that Dr. Rank has left two calling cards with black crosses on them. Nora explains to Torvald that this means that Dr. Rank has gone away to die. Torvald expresses sadness, but decides that Dr. Rank’s death might be best for everyone, since it will make Torvald and Nora “quite dependent on each other.” He tells Nora that he loves her so much that he has wished in the past that Nora’s life were threatened so that he could risk everything to save her.