Edgar nurses Catherine for the next two months. During this time, it is revealed that Catherine is pregnant. Edgar longs for a male heir, to prevent Heathcliff and Isabella from inheriting the Grange. Six weeks after she runs away, Isabella sends a letter to Edgar, announcing her marriage and begging forgiveness. He does not reply. After that, a distraught Isabella sends a letter to Nelly, questioning the humanity of Heathcliff. She tells Nelly that they are living at Wuthering Heights and begs for a visit.

After three days of starving herself, Catherine agrees to eat. She is distraught that she is dying and Edgar has not come to her, begging forgiveness. In a state of delirium, Catherine talks about her childhood with Heathcliff and speaks of her impending death. When Nelly refuses to open the window, Catherine staggers to it, throws it open, and claims to see Wuthering Heights.

Nelly ventures back to Wuthering Heights to talk with Hindley; instead, she encounters Hareton, who has no memory of her. Hareton greets her with a barrage of stones and curses — actions he learned from Heathcliff. When Heathcliff appears, Nelly runs away. The next day at the Grange, Nelly witnesses an embrace between Heathcliff and Isabella. When Catherine confronts Heathcliff about this, he tells her "I'm not your husband: you needn't be jealous of me." This leads Heathcliff to reveal that he knows Catherine has wronged him and that he will be revenged.

Heathcliff reappears suddenly one September afternoon, approximately six months after Catherine and Edgar marry. Nelly does not tell Catherine who the visitor is, but she does tell Edgar. Edgar suggests that Catherine visit the kitchen, but she insists on entertaining in the parlor. Catherine's excitement over Heathcliff's return was not the reception he expected, but he is pleased to receive it. Their words and actions reveal that Catherine and Heathcliff love each other. Heathcliff surprises everyone by stating that he is staying at Wuthering Heights.

In a drunken rage, Hindley accidentally drops Hareton over the banister, but luckily, Heathcliff is present and catches the baby. Later, in the kitchen, Catherine speaks to Nelly. Thinking they are alone, Catherine tells Nelly that Edgar asked her to marry him and that she accepted. Catherine explains that she cannot marry Heathcliff because Hindley has degraded him so much; however, she expresses her love for Heathcliff. She prefaces her remarks with "It would degrade me to marry Heathcliff," and these are the words he overhears. Catherine continues, that Heathcliff will never know how much she loves him and that "he's more myself than I am." Heathcliff leaves Wuthering Heights that night and disappears for three years. Catherine spends the entire night outdoors in the rain. She comes down with a bad chill, catches a fever, and almost dies. The Lintons allow her to recuperate at the Grange, but both Mr. and Mrs. Linton take the fever and die.

During the following summer, Frances gives birth to Hareton, but Frances dies a week later because she had been suffering from consumption. Nelly is expected to take complete control of the newborn. Hindley is distraught over the death of his wife and becomes tyrannical, forcing all the servants but Nelly and Joseph away. He also begins to treat Heathcliff more cruelly, and Heathcliff delights in Hindley's downfall. Catherine begins "to adopt a double character," behaving one way with Heathcliff and another with the Lintons. Heathcliff begins keeping track of how much time she is spending with Edgar and the Lintons, and he is angry that Catherine belittles him when he confronts her with this. Edgar arrives at the end of the argument.

Catherine remains at Thrushcross Grange for five weeks. During her stay, Mrs. Linton works with her, transforming the wild girl into a young lady. When Catherine returns to Wuthering Heights, she is barely recognizable. Hindley, treating Heathcliff as a servant, allows Catherine's playmate to step forward to greet her when she arrives. Catherine kisses Heathcliff, but while doing so, she comments upon his dirty appearance and compares him unfavorably to Edgar. Heathcliff is hurt by the changes in his friend's appearance and attitude.

Hindley returns for his father's funeral and brings a wife, Frances, along with him. Taking control of the farmhouse, Hindley immediately makes changes, moving Joseph and Nelly to the back-kitchen and prohibiting Heathcliff from receiving an education. Hindley also makes Heathcliff work in the fields. Hindley does not pay much attention to either Heathcliff or Catherine, and so they live "as savages," skipping church and playing on the moors.

As Mr. Earnshaw's health begins to fail, he becomes less tolerant of complaints about Heathcliff, and as a result, sends Hindley away to school. As Mr. Earnshaw moves closer to death, Joseph begins to have a greater influence over his master, particularly in regard to religion. Catherine continues to tease her father about her exploits with Heathcliff, never really conscious of how sick her father really is. When Mr. Earnshaw dies, Catherine and Heathcliff console one another with talk of heaven.

Recuperating from his wanderings, Lockwood asks Nelly about Heathcliff and his daughter-in-law. Nelly informs him that the widow's maiden name was Catherine Linton, the daughter of Nelly's late master and that Hareton Earnshaw is the nephew of her late master's wife. Cathy is the last of the Lintons, and Hareton is the last of the Earnshaws. Nelly also reveals that Heathcliff had married Mr. Linton's sister.