Wuthering Heights is related as a series of narratives which are themselves told to the narrator, a gentleman named Lockwood. Lockwood rents a fine house and park called Thrushcross Grange in Yorkshire, and gradually learns more and more about the histories of two local families. This is what he learns from a housekeeper, Ellen Dean, who had been with one of the two families for all of her life:
In around 1760, a gentleman-farmer named Earnshaw went from his farm, Wuthering Heights, to Liverpool on a business trip. He found there a little boy who looked like a gypsy who had apparently been abandoned on the streets, and brought the child home with him, to join his own family of his wife, his son Hindley, his daughter Catherine, a manservant named Joseph, and Ellen, who was very young at the time and working as a maid. Earnshaw named the boy Heathcliff after a son of his who had died. All the other members of the household were opposed to the introduction of a strange boy, except for Catherine, who was a little younger than Heathcliff and became fast friends with him. Hindley in particular felt as though Heathcliff had supplanted him, although he was several years older and the true son and heir. Hindley bullied Heathcliff when he could, and Heathcliff used his influence over Earnshaw to get his way. Heathcliff was a strange, silent boy, who appeared not to mind the blows he received from Hindley, although he was in fact very vindictive. Earnshaw's wife died. Hindley was sent away to college in a last attempt to turn him into a worthy son, and to ease pressures at home.
After some years, Earnshaw's health declined and he grew increasingly alienated from his family: in his peevish old age he worried that everyone disliked Heathcliff simply because Earnshaw liked him. He did not like his daughter Catherine's charming and mischievous ways. Finally he died, and Catherine and Heathcliff were very grieved, but consoled each other with thoughts of heaven.
Hindley returned, now around twenty years old. Heathcliff was about twelve and Catherine was eleven. Hindley was married to a young woman named Frances, to the surprise of everyone at Wuthering Heights. Hindley used his new power as the head of the household to reduce Heathcliff to the level of a servant, although Heathcliff and Catherine continued their intimacy. Catherine taught Heathcliff her lessons and would join him in the fields, or they would run away to the moors all day to play, never minding their punishments afterward.
One day they ran down to the Grange, a more civilized house where the Lintons lived with their children Edgar, thirteen, and Isabella, eleven. Catherine and Heathcliff despised the spoiled, delicate Linton children, and made faces and yelled at them through the window. The Lintons called for help and the wilder children fled, but Catherine was caught by a bulldog and they were brought inside. When the Lintons found out that the girl was Miss Earnshaw, they took good care of her and threw Heathcliff out.
Catherine stayed at the Grange for five weeks, and came home dressed and acting like a proper young lady, to the delight of Hindley and his wife, and to Heathcliff's sorrow––he felt as though she had moved beyond him. Over the next few years, Catherine struggled to both maintain her relationship with Heathcliff, and socialize with the elegant Linton children.
Frances gave birth to a son, Hareton, and died soon after of tuberculosis. Hindley gave in to wild despair and alcoholism, and the household fell into chaos. Heathcliff was harshly treated, and came to hate Hindley more and more. Edgar Linton fell in love with Catherine, who was attracted by his wealth and genteel manners, although she loved Heathcliff much more seriously. Edgar and Catherine became engaged, and Heathcliff ran away. Catherine fell ill after looking for Heathcliff all night in a storm, and went to the Grange to get better. The Linton parents caught her fever and died of it. Edgar and Catherine were married when she was 18 or 19.
They lived fairly harmoniously together for almost a year––then Heathcliff returned. He had mysteriously acquired gentlemanly manners, education, and some money. Catherine was overjoyed to see him, Edgar considerably less so. Heathcliff stayed at Wuthering Heights, where he gradually gained financial control by paying Hindley's gambling debts. Heathcliff's relationship with the Linton household became more and more strained as Edgar grew extremely unhappy with Heathcliff's relationship with Catherine. Finally there was a violent quarrel: Heathcliff left the Grange to avoid being thrown out by Edgar's servants, Catherine was angry at both of the men, and Edgar was furious at Heathcliff and displeased by his wife's behavior. Catherine shut herself in her room for several days. In the meantime, Heathcliff eloped with Isabella (who was struck by his romantic appearance) by way of revenge on Edgar. Edgar could not forgive Isabella's betrayal of him, and did not try to stop the marriage. Catherine became extremely ill, feverish and delirious, and nearly died though she was carefully tended by Edgar once he discovered her condition.
A few months later, Catherine was still very delicate and looked as though she would probably die. She was pregnant. Heathcliff and Isabella returned to Wuthering Heights, and Isabella wrote to Ellen describing how brutally she was mistreated by her savage husband, and how much she regretted her marriage. Ellen went to visit them to see if she could improve Isabella's situation. She told them about Catherine's condition, and Heathcliff asked to see her.
A few days later, Heathcliff came to the Grange while Edgar was at church. He had a passionate reunion with Catherine, in which they forgave each other as much as possible for their mutual betrayals. Catherine fainted, Edgar returned, and Heathcliff left. Catherine died that night after giving birth to a daughter. Edgar was terribly grieved and Heathcliff wildly so––he begged Catherine's ghost to haunt him. A few days later, Hindley tried to murder Heathcliff, but Heathcliff almost murdered him instead. Isabella escaped from Wuthering Heights and went to live close to London, where she gave birth to a son, Linton. Hindley died a few months after his sister Catherine.
Catherine and Edgar's daughter, Cathy, grew to be a beloved and charming child. She was brought up entirely within the confines of the Grange, and was entirely unaware of the existence of Wuthering Heights, Heathcliff, or her cousin Hareton there. Once she found the farmhouse while exploring the moors, and was upset to think that such an ignorant rustic as Hareton could be related to her. Ellen ordered her not to return there and explained about Heathcliff's feud with Cathy's father, Edgar.
Isabella died when Linton was about twelve years old, and Edgar went to fetch him to the Grange. Linton was a peevish and effeminate boy, but Cathy was pleased to have a playmate. That very day, however, Heathcliff sent Joseph to fetch his son to Wuthering Heights, and when Cathy woke up the next morning her cousin was gone. Though sad at first, she soon got over it, and continued her happy childhood.
On her sixteenth birthday, Cathy and Ellen strayed onto Heathcliff's lands, and he invited them into Wuthering Heights to see Linton. Cathy was pleased to renew her acquaintance, and Heathcliff was eager to promote a romance between the two cousins, so as to ensure himself of Edgar's land when he died. When they returned home, Edgar forbade Cathy to continue visiting there, and said that Heathcliff was an evil man. Cathy then began a secret correspondence with Linton, which became an exchange of love letters. Ellen found out and put an end to it.
Edgar became ill. Heathcliff asked Cathy to return to Wuthering Heights because Linton was breaking his heart for her. She did so, and found Linton to be a bullying invalid, but not without charm. Ellen fell ill as well and was unable to prevent Cathy from visiting Wuthering Heights every day. Cathy felt obliged to help Linton, and despised Hareton for being clumsy and illiterate. Ellen told Edgar about the visits when she found out, and he forbade Cathy to go any more.
Edgar was in poor health and didn't know about Linton's equally bad health and bad character, so he thought it would be good for Cathy to marry him––since Linton and not Cathy would most likely inherit the Grange. A system was fixed up in which Linton and Cathy met outside. Linton was increasingly ill, and seemed to be terrified of something––as it turned out, his father was forcing him to court Cathy. Heathcliff feared Linton would die before Edgar did, so eventually he all but kidnapped Cathy and Ellen, and told them Cathy couldn't go home to see her dying father until she married Linton. Cathy did marry Linton, and escaped in time to see Edgar before he died.
After Edgar's funeral (he was buried next to his wife) Heathcliff fetched Cathy to Wuthering Heights to take care of Linton, who was dying, and to free up the Grange so he could rent it out (to Lockwood, in fact). Heathcliff told Ellen that he was still obsessed by his beloved Catherine, and had gone to gaze at her long-dead body when her coffin was uncovered by the digging of Edgar's grave.
Cathy had to care for Linton alone, and when he died, she maintained an unfriendly attitude to the household: Heathcliff, Hareton (who was in love with her), Joseph, and Zillah, the housekeeper. As time passed, however, she became lonely enough to seek Hareton's company, and began teaching him to read.
This is around the time of Lockwood's time at the Grange. He leaves the area for several months, and when he returns, he learns that while he was gone:
Heathcliff began to act more and more strangely, and became incapable of concentrating on the world around him, as though Catherine's ghost wouldn't let him. He all but stopped eating and sleeping, and Ellen found him dead one morning, with a savage smile on his face. He was buried next to Catherine, as he had wished. Hareton grieved for him, but was too happy with the younger Cathy to be inconsolable. When the novel ends, Hareton and Cathy plan to marry and move to the Grange.