Lockwood becomes sick after his traumatic experience at Wuthering Heights, and—as he writes in his diary—spends four weeks in misery. Heathcliff pays him a visit, and afterward Lockwood summons Nelly Dean and demands to know the rest of her story. How did Heathcliff, the oppressed and reviled outcast, make his fortune and acquire both Wuthering Heights and Thrushcross Grange? Nelly says that she doesn't know how Heathcliff spent the three years that he was away, and that it was at this time that he apparently acquired his wealth. But she agrees to continue with her tale.
About six months after Catherine’s marriage to Edgar Linton, Heathcliff returns home, surprising Nelly at Thrushcross Grange. When he comes indoors, Catherine becomes almost giddy with happiness at the sight of him, and their obvious affection for one another makes Edgar uncomfortable and jealous. Heathcliff has grown into a polished, gentlemanly, and physically impressive man, though some hint of savagery remains in his eyes.
He announces that Hindley has invited him to stay at Wuthering Heights. This surprises both Catherine and Nelly, but Heathcliff tells Catherine that when he sought Nelly at Wuthering Heights earlier that day, he came across Hindley in a card game with his rough friends. Heathcliff joined them in the gambling, and, because his reckless bids seemed to bespeak a great wealth, Hindley excitedly invited him to return.
Catherine and Isabella begin to visit Wuthering Heights quite often, and Heathcliff returns the favor by calling at the Grange. Isabella begins to fall in love with Heathcliff, who, despite his obvious love for Catherine, does nothing to discourage her sister-in-law’s affections. Nelly suspects that he harbors wicked and vengeful motives, and vows to watch him closely.
Nelly travels to Wuthering Heights to talk with Hindley, but instead she finds Hareton, who throws stones at her and curses. Nelly learns from Hareton that Heathcliff has taught the boy to swear at his father, Hindley, and has forbidden the curate, who offered to educate Hareton, to set foot on the property. Heathcliff appears, and Nelly flees.
The next day, at the Grange, Nelly observes Heathcliff embracing Isabella. In the kitchen, Catherine demands that Heathcliff tell her his true feelings about Isabella. She offers to convince Edgar to permit the marriage if Heathcliff truly loves the woman. Heathcliff scorns this idea, however, declaring that Catherine has wronged him by marrying Edgar, and that he intends to exact revenge. Nelly informs Edgar of the encounter occurring between Catherine and Heathcliff in the kitchen, and Edgar storms in and orders Heathcliff off of his property. When Heathcliff refuses to leave, Edgar summons his servants for help.
However, Catherine locks herself and the two men inside the kitchen and throws the key into the fire, forcing Edgar to confront Heathcliff without the help of additional men. Overcome with fear and shame, Edgar hides his face. Still, Catherine’s taunts goad Edgar into striking Heathcliff a blow to the throat, after which Edgar exits through the garden. In terror of the larger and stronger Heathcliff, Edgar hurries to find help, and Heathcliff, deciding that he cannot fight three armed servants, departs.
In a rage, Edgar declares that Catherine must choose between Heathcliff and himself. Catherine refuses to speak to him, locking herself in a room and refusing to eat. Two days pass in this way, and Edgar warns Isabella that if she pursues Heathcliff, he will cast her out of the Linton family.
At last, Catherine permits the servants to bring her food. Hysterical, she believes that she is dying, and cannot understand why Edgar has not come to her. She rants about her childhood with Heathcliff on the moors, and speaks obsessively about death. Nelly, worried that her mistress will catch a chill, refuses to open the window. Catherine manages to stumble to the window and force it open; from the window, she believes she can see Wuthering Heights. Catherine says that even though she will die, her spirit will never be at rest until she can be with Heathcliff. Edgar arrives and is shocked to find Catherine in such a weak condition. Nelly goes to fetch a doctor. The doctor professes himself cautiously optimistic for a successful recovery.
That very night, Isabella and Heathcliff elope. Furious, Edgar declares that Isabella is now his sister only in name. Yet he does not disown her, saying instead that she has disowned him.
Edgar and Nelly spend two months nursing Catherine through her illness, and, though she never entirely recovers, she learns that she has become pregnant. Six weeks after Isabella and Heathcliff’s marriage, Isabella sends a letter to Edgar begging his forgiveness. When Edgar ignores her pleas, she sends a letter to Nelly, describing her horrible experiences at Wuthering Heights. In her letter, she explains that Hindley, Joseph, and Hareton have all treated her cruelly, and that Heathcliff declares that since he cannot punish Edgar for causing Catherine’s illness, he will punish Isabella in his place.
Isabella also tells Nelly that Hindley has developed a mad obsession with Heathcliff, who has assumed the position of power at Wuthering Heights. Hindley hopes that somehow he will be able to obtain Heathcliff’s vast fortune for himself, and he has shown Isabella the weapon with which he hopes to kill Heathcliff—a pistol with a knife attached to its barrel. Isabella says that she has made a terrible mistake, and she begs Nelly to visit her at Wuthering Heights, where she and Heathcliff are now living.
Nelly grants Isabella’s request and goes to the manor, but Edgar continues to spurn his sister’s appeals for forgiveness. When Nelly arrives, Heathcliff presses her for news of Catherine and asks if he may come see her. Nelly refuses to allow him to come to the Grange, however, and, enraged, Heathcliff threatens that he will hold Nelly a prisoner at Wuthering Heights and go alone. Terrified by that possibility, Nelly agrees to carry a letter from Heathcliff to Catherine.
Heathcliff, who seemed an almost superhuman figure even at his most oppressed, emerges in these chapters as a demonically charismatic, powerful, and villainous man, capable of extreme cruelties. Tortured by the depth of his love for Catherine, by his sense that she has betrayed him, and by his hatred of Hindley and the Linton family for making him seem unworthy of her, Heathcliff dedicates himself to an elaborate plan for revenge. The execution of this plan occupies much of the rest of the novel.
Though Heathcliff’s first reunion with Catherine seems joyful, Nelly is right to fear his return, for he quickly exhibits his ardent malice, first through his treatment of the pathetic wretch Hindley, and then through his merciless abuse of the innocent Isabella. But though his destructive cruelty makes him the villain of the book, Heathcliff never loses his status as a sympathetic character. Although one can hardly condone his actions, it is difficult not to commiserate with him.
This ambiguity in Heathcliff’s character has sparked much discussion among critics, who debate whether his role in the novel is that of hero or villain. In some sense, he fulfills both roles. He certainly behaves cruelly and harmfully toward many of the other characters; yet, because he does so out of the pain of his love for Catherine, the reader remains just as attuned to Heathcliff’s own misery as to the misery he causes in others. The love between Catherine and Heathcliff constitutes the center of Wuthering Heights both thematically and emotionally, and, if one is to respond at all to the novel, it is difficult to resist sympathizing with that love. Correspondingly, as a participant in this love story, Heathcliff never becomes an entirely inhuman or incomprehensible character to the reader, no matter how sadistically he behaves.
Many scholars believe that Brontë intended her novel to be a moralizing, cautionary tale about the dangers of loving too deeply. If this is true, then one might argue that the book, in creating such charismatic main characters as Heathcliff and Catherine, defeats its own purpose. For instance, Isabella, though innocent and morally pure, never exerts the same power over the reader’s imagination as Heathcliff and Catherine. As a result, it becomes unnervingly easy to overlook Isabella’s suffering, even though her suffering would otherwise function as one of the novel’s strongest pieces of evidence in its condemnation of obsessive passions.
Similarly, Heathcliff suffers the ill treatment of characters who seem his intellectual and spiritual inferiors; thus when he seeks revenge on a brute such as Hindley, the reader secretly wishes him success. As a result, once again, Brontë’s strong characterization of Heathcliff undermines any possible intent she might have had to warn her readers about the perils of an overly intense love.
In addition to exploring the character of Heathcliff as a grown man, this section casts some light on the character of Nelly Dean as a narrator. Her narrative has always shown certain biases, and throughout the book she harshly criticizes Catherine’s behavior, calling her spoiled, proud, arrogant, thoughtless, selfish, naïve, and cruel. It is true that Catherine can be each of those things, but it also seems clear that Nelly is jealous of Catherine’s beauty, wealth, and social station. It is important to remember that Nelly is not much older than Catherine and grew up serving her.
Some readers have speculated that Nelly’s jealousy may also arise from a passion for Edgar Linton—whom she praises extravagantly throughout the novel—or even for Heathcliff, whom she often heatedly denounces. This section of the book offers some evidence for the latter view. For instance, when Catherine teasingly tells Heathcliff in Chapter X that Isabella has fallen in love with him, she does so by saying, “Heathcliff, I’m proud to show you, at last, somebody that dotes on you more than myself. I expect you to feel flattered.”
She then says, “Nay, it’s not Nelly; don’t look at her!” This comment suggests that Heathcliff looks at Nelly after Catherine’s first statement. Perhaps in the past he has suspected Nelly of having feelings for him. Certainly, a reader might interpret Catherine’s words in a different manner. Nevertheless, Catherine’s comments substantiate the idea that Nelly’s feelings for the other characters in the novel are deeper and more complicated than she reveals to Lockwood.