Heathcliff wants revenge so badly that he's willing to destroy everyone at Wuthering Heights and Thrushcross Grange. Heathcliff cruelly uses Hareton, Catherine, and Linton, his own son, to get his revenge. Heathcliff brags that he's changed Hareton from an intelligent boy into an "ignorant brute" while he's raised his son, who is weak and selfish, to be the master over Hareton. He imprisons Catherine and forces her to marry Linton and then forces Linton to make Heathcliff the beneficiary of his and Catherine's property. After Linton dies, Catherine has to stay with Heathcliff since she is now poor and alone. He brutalizes Hareton until Catherine and Hareton fall in love. Catherine and Hareton are drawn to one another because of their circumstances, but they do fall in love and will marry at the end of the novel. Although Heathcliff has degraded Hareton, Hareton cries over Heathcliff's body when he dies. Hareton is changed when he falls in love with Catherine, who teaches him to read.
The only ones who survive Heathcliff's revenge are Catherine and Hareton. By the end of the novel, there is hope that they can overcome the hate and cruelty that they've been exposed to all their lives.