Mrs. Elvsted and Hedda sleep in the living room, waiting for Tesman, Brack and Lovborg to return. Berta enters, giving Mrs. Elvsted false hope that the men have arrived home, but she is only carrying a letter for Tesman. Hedda is irritated that the men still aren't there, but theorizes that the men simply stayed at Judge Brack's house out of consideration, so that they wouldn't wake the women. Hedda convinces Mrs. Elvsted to go try and sleep, saying that she'll continue waiting for the men. Mrs. Elvsted goes to Hedda's room.
Hedda reprimands Berta for having allowed the room to become so cold, but the doorbell rings and Hedda bids her to answer it, saying she'll tend to the fire herself. A moment later, Tesman enters. Tesman tells Hedda that they had arrived at the party an hour too early, and so Eilert had passed the time by reading to him from his new book. He remarks that he was just dazzled by it, but Hedda replies that she "doesn't care" about the book; what she's interested in is the goings-on of the previous night. Tesman tells her that Lovborg began to drink, and once he was intoxicated he began making speeches about his "muse" - the unnamed woman who inspired his work. Hedda asks Tesman if Lovborg named this woman, but Tesman says that although he did not, he assumes that he was referring to Mrs. Elvsted. The men escorted Lovborg home, but on the way, he dropped his new manuscript, which Tesman picked up and has brought home with him.
Hedda's interest is piqued by this turn of events. She asks Tesman whether anyone knows that he has the manuscript, and he replies that no one does. He says that for Lovborg's sake he didn't tell a soul, and simply plans to return it in the morning. Hedda is clearly conjuring some sort of plan, but she distracts Tesman by handing over the letter that arrived earlier. Tesman opens the letter and learns that Aunt Rina is "at death's door" and that he must come immediately to the house. He begs Hedda to come with him, but Hedda is repulsed by the very idea of being in the presence of death. Berta enters and announces that Brack has arrived, so Tesman makes a hasty exit to avoid him. Just before he leaves, Hedda convinces her husband to give her Lovborg's manuscript for safekeeping.
Hedda Gabler is set in a single location - the Tesman house - and, even more incredibly, in only one room in that house. Ibsen carefully manipulates who is in the drawing room at any given time, ensuring that his dramatic purposes are served without sacrificing the credibility of story. There are a few moments when the exits seem tenuous - Lovborg arriving as soon as Brack leaves, Tesman arriving when Mrs. Elvsted retires - but these machinations generally appear to be in the service of time compression, rather than plot convenience.
Hedda, in a strange way, seems to represent the collective unconscious in the play. Her husband, for instance, is clearly jealous of Eljert's new book, and holds onto it as if he has every intention of destroying it, but ultimately resigns himself to the fact that it must be returned. By handing it to Hedda, however, his unconscious desires will come to fruition. The same holds true for Lovborg. He is clearly a self-destructive man - or, in a sense, Hedda's puppet in the wake of her rejection. His unconscious desire is to be freed from her, to be freed from the constant thoughts that plague him. By the end of Act III, however, Hedda will do to Lovborg what she's done to her husband: appropriate his desires as her own. The book will burn, and Lovborg will find the "courage" to die.
A quote from Ibsen offers a great deal of insight as to the motivations behind Hedda's actions: "Hedda's desperation is a conviction that life must offer so many possibilities of happiness, but that she can't catch sight of them. It is the want of a goal in life that torments her." Hedda lives for the rush of a moment, the adrenaline that comes with controlling life and determining the fates of others - for it is only this that gives her the fleeting sense of purpose and control that makes her feel alive. Ultimately, though, the boredom keeps returning - that feeling that she ultimately has no control over her own fate. She had to marry a man she didn't love simply because her time ran out; she is carrying a child that will dictate her future; she is ultimately at the mercy of the men who covet her.
Hedda wants to keep the manuscript not because she knows exactly what she's going to do with it, but because it gives her an ephemeral sense of control over other's lives. In an instant, she is transformed from the observer to the puppetmaster, holding a bunch of pieces of paper that ultimately control all of the main characters in the play. Tesman is deeply jealous of the book and would be freed by its eradication, Mrs. Elvsted needs the book in order for Lovborg to regain his reputation and ultimately marry her, and Lovborg needs the book for a number of reasons, not the least of which is that it remains his only connection to Hedda, his "muse". Now that Hedda has the book, however, she has all of these characters lodged firmly in her web. It is not out of malice that she will continue her machinations, but rather out of her desire, as Ibsen says, to find happiness in the fleeting accomplishment of a goal.