That winter, Edgar falls ill and Nelly becomes Cathy's main companion. One day, as the two walk in the garden, Cathy climbs the wall in an effort to get some fruit. In the process, her hat falls over the wall. Cathy, with Nelly's permission, climbs down the wall to get it, but then finds herself unable to climb back.
The wall around the garden symbolizes the boundary between nature and civilization. Besides being tomboyish, Cathy's climbing over the wall shows her adventurous spirit and her connection to nature.
As Nelly searches for a key to the gate in the wall, Heathcliff appears. He admonishes Cathy for ending her correspondence with Linton, adding that he suspects she was cruelly playing with Linton. He then says that he will be away from Wuthering Heights for a week, and that she should visit Linton, who he thinks may be dying of a broken heart. Cathy feels so guilty that she decides to go to Wuthering Heights the next morning. Nelly agrees to go only because she thinks the sight of Linton will show Cathy that Heathcliff is lying.
Heathcliff further engineers the relationship between Cathy and Linton, not because he wants them to be happy together (they are clearly a terrible match), but simply to further his revenge.