In the Helmer living‑room, after the dance, Mrs Linde sits alone, waiting for Krogstad. When he enters, she urges him to speak privately; they argue about his past, her poverty, and her recent discovery that she might take Krogstad’s former bank position. Krogstad, feeling like a shipwrecked man, proposes that they join forces, but Mrs Linde rejects his selfish offer and instead asks him to retrieve the blackmail letter from the mailbox. He agrees to wait for Torvald and then leave.

Soon Torvald returns with Nora, who is still in her tarantella costume. Torvald forces Nora back into the room, scolds her for staying up, and boasts about her performance. Mrs Linde greets them, and they exchange superficial compliments. Nora, urged by Mrs Linde, refuses to tell Torvald about Krogstad’s letter, but Torvald soon discovers a stack of letters in the mailbox, including Krogstad’s threatening note. He reads it, mistakenly believes the letter will be returned, and exclaims that they are “saved.” He tears up the bond and the letters and throws them into the stove, thinking the danger is gone.

Doctor Rank then arrives, announcing his good spirits but also hinting at his imminent death through black‑crossed cards. He converses with Torvald and Nora about his recent work and plans for future costume balls, then leaves.

Later, Torvald locks the hall door, searches the letter‑box, and finds the black‑crossed cards indicating Rank’s resignation and death. He interprets this as a further crisis but decides to burn the letters anyway. Nora, now aware that the secret is exposed, confronts Torvald. She declares she has loved him out of duty, not genuine affection, and that she has never been truly happy. She accuses Torvald of treating her like a doll and his father’s doll‑child, and announces she will leave the marriage to find herself and her own education. Torvald protests, attempts to prevent her departure, and claims she is abandoning her duties as wife and mother. Nora remains steadfast, saying she will take nothing from him and will not return. She gathers her cloak and a small bag, says good‑byes, and exits the house, leaving Torvald devastated and alone. The scene ends with Torvald sinking into despair as the door shuts behind Nora.