Zillah brings Lockwood to a room that Heathcliff usually doesn't allow anyone to stay in. Left alone, Lockwood notices three names scratched into the paint of the bed: Catherine Earnshaw, Catherine Heathcliff, and Catherine Linton. Lockwood also finds a 25-year-old diary, written by Catherine Earnshaw. He reads an entry from a time just after her father died, in which her older brother Hindley makes Catherine and Heathcliff listen to Joseph's dull sermons. From the entry it's clear that Hindley hated Heathcliff, but that Catherine and Heathcliff were close.
That night Lockwood has a nightmare in which he breaks a window to get some air, and a child grabs his hand. She says her name is Catherine Linton and begs to enter, claiming she's been trying to get in for twenty years. Lockwood fights her and frees himself. She continues to beg, and he cries out. His yell carries into the real world—Heathcliff hears it and comes running. He's upset to find Lockwood in the room, while Lockwood's upset over the ghost. Lockwood describes his nightmare to Heathcliff, who becomes livid when Lockwood says the dream-waif deserves to be punished. Heathcliff, sobbing, opens the window and shouts for Catherine to come in.
This scene contains the one truly supernatural event in the novel, with Lockwood dreaming of the real Catherine Linton. But it's Heathcliff's response to the dream which is most interesting, the way that he seems to want, or even need, this ghost to haunt him. Heathcliff's all-consuming love and passion for Catherine is made clear in this scene, and that love is connected to nature when Heathcliff throws open the window in order to speak with Catherine.
The next morning Heathcliff escorts Lockwood home. The servants of Thrushcross Grange are overjoyed to see Lockwood—they feared he'd died in the storm. But Lockwood, in no mood for company, locks himself in the study.
While Heathcliff opens the window to the storm to try to speak with Catherine, Lockwood locks himself inside to escape all that passion. Nature vs. civilization.