The play opens at Christmas time as Nora Helmer enters her home carrying a number of packages. Nora's husband Torvald is working in his study when she arrives. He playfully rebukes her for spending so much money on Christmas gifts, calling her his "little squirrel". He teases her about how she spent weeks making gifts and ornaments by hand last year because money was scarce. This year Torvald is due a promotion at the bank where he works, so Nora feels that they can let themselves go a little. The maid announces two visitors: Mrs. Kristine Linde, an old friend of Nora's, who has come seeking employment, and Dr. Rank, a close friend of the family, who is let into the study. Kristine has had a difficult few years, ever since her husband died, leaving her with no money or children. Nora explains that things have not been easy for them either: Torvald became sick and they had to travel to Italy so he could recover. Kristine further explains that when her mother was ill, she had to take care of her brothers, but now that they are grown she feels her life is "unspeakably empty". Nora promises to talk to Torvald about finding her a job. Kristine gently tells Nora that she is like a child. Nora is offended, so she reveals that she borrowed money so they could travel to Italy in order to improve Torvald's health. She told Torvald that her father gave her the money, but in fact she managed to illegally borrow it without his knowledge. Over the years she has been secretly working and saving up to pay it off.
Krogstad, a lower-level employee at Torvald's bank arrives and goes into the study. Nora is clearly uneasy when she sees him. Dr. Rank leaves the study and mentions that he feels wretched, though, like everyone, he wants to go on living. In contrast to his physical illness, he says that the man in the study, Krogstad, is "morally diseased".
After the meeting with Krogstad, Torvald comes out of the study. Nora asks him if he can give Kristine a position at the bank and Torvald is very positive, saying that this is a fortunate moment, as a position has just become available. Torvald, Kristine, and Dr. Rank leave the house, leaving Nora alone. The nanny returns with the children and Nora plays with them for a while until Krogstad creeps into the living room and surprises her. Krogstad tells Nora that Torvald intends to fire him at the bank and asks her to intercede with Torvald to allow him to keep his job. She refuses and Krogstad threatens to blackmail her about the loan she took out for the trip to Italy; he knows that she obtained this loan by forging her father's signature. Krogstad leaves and when Torvald returns she tries to convince him not to fire Krogstad. Torvald refuses to hear her pleas, explaining that Krogstad is a liar and a hypocrite and that he committed a terrible crime: he forged someone's name. Torvald feels physically ill in his presence of a man "poisoning his own children with lies and dissimulation".
Kristine arrives to help Nora repair a dress for a costume function that she and Torvald plan to attend the next day. Torvald returns from the bank, and Nora pleads with him to reinstate Krogstad, claiming she is worried Krogstad will publish libelous articles about Torvald and ruin his career. Torvald dismisses her fears and explains that, although Krogstad is a good worker and seems to have turned his life around, he must be fired because he is not deferential enough to Torvald in front of other bank personnel. Torvald then retires to study his work.
Dr. Rank, a family friend, arrives. Nora asks him for a favour, but Rank responds by revealing that he has entered the terminal stage of tuberculosis of the spine and that he has always been secretly in love with her. Nora tries to deny the first revelation and make light of it but is more disturbed by his declaration of love. She tries clumsily to tell him that she is not in love with him but that she loves him dearly as a friend.
Desperate after being fired by Torvald, Krogstad arrives at the house. Nora convinces Dr. Rank to go into Torvald's study so he will not see Krogstad. When Krogstad confronts Nora, he declares that he no longer cares about the remaining balance of Nora's loan, but that he will instead preserve the associated bond in order to blackmail Torvald into not only keeping him employed but also promoting him as well. Nora explains that she has done her best to persuade her husband, but he refuses to change his mind. Krogstad informs Nora that he has written a letter detailing her crime (forging her father's signature of surety on the bond) and put it in Torvald's mailbox, which is locked.
Nora tells Kristine of her difficult situation. Kristine says that she and Krogstad are still in love and promises to try to convince him to relent.
Torvald enters and tries to retrieve his mail, but Nora distracts him by begging him to help her with the dance she has been rehearsing for the costume party, feigning anxiety about performing. She dances so badly and acts so childishly that Torvald agrees to spend the whole evening coaching her. When the others go to dinner, Nora stays behind for a few minutes and contemplates killing herself to save her husband from the shame of the revelation of her crime and (more importantly) to pre-empt any gallant gesture on his part to save her reputation.
Kristine tells Krogstad that she only married her husband because she had no other means to support her sick mother and young siblings and that she has returned to offer him her love again. She believes that he would not have stooped to unethical behavior if he had not been devastated by her abandonment and been in dire financial straits. Krogstad is moved and offers to take back his letter to Torvald. However, Kristine decides that Torvald should know the truth for the sake of his and Nora's marriage.
After literally dragging Nora home from the party, Torvald goes to check his mail, but is interrupted by Dr. Rank, who has followed them. Dr. Rank chats for a while, conveying obliquely to Nora that this is a final goodbye, as he has determined that his death is near. Dr. Rank leaves, and Torvald retrieves his letters. As he reads them, Nora steels herself to take her life. Torvald confronts her with Krogstad's letter. Enraged, he declares that he is now completely in Krogstad's power – he must yield to Krogstad's demands and keep quiet about the whole affair. He berates Nora, calling her a dishonest and immoral woman and telling her that she is unfit to raise their children. He says that from now on their marriage will be only a matter of appearances.
A maid enters, delivering a letter to Nora. The letter is from Krogstad, yet Torvald demands to read the letter, taking it from Nora. Torvald exults that he is saved, as Krogstad has returned the incriminating bond, which Torvald immediately burns along with Krogstad's letters. He takes back his harsh words to his wife and tells her that he forgives her. Nora realizes that her husband is not the strong and gallant man she thought he was and that he truly loves himself more than he does her.
Torvald explains that, when a man has forgiven his wife, it makes him love her all the more since it reminds him that she is totally dependent on him, like a child. He dismisses the fact that Nora had to make the agonizing choice between her conscience and his health, and ignores her years of secret efforts to free them from the ensuing obligations and danger of loss of reputation. He preserves his peace of mind by thinking of the incident as a mere mistake that she made owing to her dumbness, one of her most endearing feminine traits.
We must come to a final settlement, Torvald. During eight whole years. . . we have never exchanged one serious word about serious things.Nora, in Ibsen's A Doll's House (1879)
Nora tells Torvald that she is leaving him to live alone so that she can find out who she is and what she believes and decide what to do with her life. She says that she has been treated like a doll to play with for her whole life, first by her father and then by him. Concerned for the family reputation, Torvald insists that she fulfill her duty as a wife and mother, but Nora says that her first duties are to herself and that she cannot be a good mother or wife without learning to be more than a plaything. She reveals that she had expected that he would want to sacrifice his reputation for hers and that she had planned to kill herself to prevent him from doing so. She now realizes that Torvald is not at all the kind of person she had believed him to be and that their marriage has been based on mutual fantasies and misunderstanding.
Torvald is unable to comprehend Nora's point of view, since it contradicts all that he has been taught about the female mind throughout his life. Furthermore, he is so narcissistic that it is impossible for him to understand how he appears to her, as selfish, hypocritical and more concerned with public reputation than with actual morality. Nora leaves her keys and wedding ring and, as Torvald breaks down and begins to cry, baffled by what has happened, Nora leaves the house, slamming the door behind herself. Whether or not she ever comes back is never made clear.
Ibsen's German agent felt that the original ending would not play well in German theatres; therefore, for it to be considered acceptable, Ibsen was forced to write an alternative ending for the German premiere. In this ending, Nora is led to her children after having argued with Torvald. Seeing them, she collapses, and the curtain is brought down. Ibsen later called the ending a disgrace to the original play and referred to it as a 'barbaric outrage'.