The major conflict of Wuthering Heights revolves around Heathcliff’s passion for Catherine Earnshaw and the barriers to it created by their opposed class positions. Heathcliff grew up alongside Catherine, and she loves him so much that she tells Nelly, “He’s more myself than I am.” Nonetheless, she cannot imagine marrying him. Even though Heathcliff was raised with the Earnshaw children and deeply beloved by old Mr. Earnshaw and Catherine alike, he will never be seen as an equal of the Wuthering Heights family. This class-based exclusion drives him to become obsessed with gaining control of the property and seeing his descendants dominate the descendants of the Earnshaws. Because Heathcliff cannot be with Catherine, his desire for her becomes a warped quest to gain status and power and to punish anyone who has stood in his way.
The inciting action begins when Heathcliff is adopted by old Mr. Earnshaw as a young child. He quickly becomes someone who is both a part of the family and yet excluded from it, and as Nelly notes, this strange tension meant that “he bred bad feeling in the house.” Heathcliff’s growing closeness with Catherine increases the conflict, and when Hindley Earnshaw becomes the master of Wuthering Heights after the death of his father, tensions are high. The conflict continues when Hindley is devastated by the loss of his wife and becomes especially vengeful towards Heathcliff and is intensified when Catherine marries Edgar Linton and Heathcliff marries Isabella. An initial climax occurs when a violent argument between Catherine, Edgar, and Heathcliff triggers Catherine's death. As she laments to Heathcliff, “You and Edgar have broken my heart…You have killed me—and thriven on it.”
The major conflict of Heathcliff’s doomed longing for Catherine now continues in perpetuity because he can never have her, but he can also never let go of her. He begs, “Be with me always—take any form—drive me mad! Only do not leave me in this abyss where I cannot find you.” As a result, Heathcliff’s desire focuses on punishing the Earnshaw family by ensuring their last descendant, Hareton, grows up illiterate and unable to ever inherit the property to which he is entitled. Heathcliff also becomes obsessed with securing the marriage of his son to Catherine and Edgar's daughter, Cathy Linton, as a way to solidify access to Thrushcross Grange. This secondary conflict reaches a climax with Heathcliff dying a mysterious death, worn out by his thirst for revenge and his longing to be reunited with the elder Catherine. This climax resolves the central conflict by allowing a form of union with Catherine which would never have been possible during her life.