On Heathcliff’s next visit to Thrushcross Grange, Nelly accidentally saw him in an affair with Isabella. She told Catherine about it. Catherine was enraged at Heathcliff, but Heathcliff was as angry. He yelled at her that she was just torturing him by being nice to him while staying married to Edgar.
Nelly told Edgar about the quarrel, causing him to interfere. Sensing a coming fight, Edgar signaled for her to fetch some men. Catherine wanted the two men to fight fair and square, though, and locked the room. By some luck Edgar managed to choke Heathcliff and efficiently used the short time Heathcliff needed to catch his breath to go through the back door. He came back with a coachman and two gardeners, which made Heathcliff decide to escape for now.
Catherine then had a fit. Edgar was worried, but Nelly convinced him not to, assuring him his wife was just being spoiled. Hearing that, Catherine glared at Nelly and rushed to her room, refusing any food.