The deputation (from which John Barton is mysteriously absent) goes to meet the mill-owners and address the striking workers' grievances. The owners are divided amongst themselves, some arguing for concession, and some who want to refuse the workers' demands. While the owners are discussing their plan of action amongst themselves, Harry Carson jumps up and declares that they should not give in. They call the deputation back into the room, and Harry Carson draws a cruel cartoon of the ragged men before him. The mill-owners inform the deputation that they have voted against concession.
Later that evening, the workers have a meeting in a pub. A delegate from London gives a rousing speech about the power of banding together. Barton, meanwhile, explains why he was missing that morning. He was visiting a worker who was imprisoned for throwing vitriol at a countryside weaver. The guilty worker asked Barton to visit his victim in the hospital and beg forgiveness on his behalf, so Barton went. After the meeting, Barton declares that there can be no more violence against the imported workers. He encourages his colleagues to blame the mill owners for all the suffering and not to take out their grievances on men from their own class. All the workers swear an oath and anonymously draw lots to see who will make the mill owners pay - by murdering one of them.
The following Thursday, Will visits Mary to tell her that he must leave for Liverpool that night and confesses that he loves Margaret. When John Barton comes home, he is rude to Will, who is on his way out. Barton refuses to eat dinner and disappears to his room. Job comes down to visit, but is disappointed that Barton will not come downstairs. When he finally does come to the dinner table, Barton is tight-lipped about his evening's plans. Before leaving the house, John Barton sees Mary standing bewildered in the open door and goes to embrace her. Later, Margaret returns with news that Alice has had a stroke. Mary plans to go to Alice's home in the morning and suffers through a sleepless night.
That same evening, the three Carson sisters, Helen, Amy and Sophy, discuss the previous night’s ball and Harry’s shameless flirtation with all the pretty girls. Their nurse enters the room with the shocking news that Harry is dead - murdered by a shot to his temple. The nurse begs Sophy to break the news to her father, so the two women go to the dining room. As the news comes out, the Carson household erupts in outrage and mourning. Mr. Carson offers a one-thousand pound reward for the capture of his son’s killer. A policeman mentions that a young man from the foundry was overheard arguing with Harry and threatening him over a young woman. Mr. Carson then pulls his distraught wife away from Harry's body, although she refuses to accept that her son is dead. Carson demands that the offending criminal be apprehended swiftly and hanged within the week.
Mary wakes up late and is late for work, but Margaret has already gone to Alice’s bedside and spent the night there. Mary goes to the Wilsons' house and sees Alice, who is in a happy delirium remembering her childhood. Mary promises to return that night to relieve Mrs. Davenport who has been helping with Alice. Margaret also wishes to help, but her blindness prevents her from being an efficient nurse. Mary looks forward to spending the evening with Jem. She learns that Jem did not return home until two or three that morning.
When she arrives at Miss Simmonds, Mary learns of Harry’s murder. Sally chides Mary for treating Harry coldly. Mary returns home thinking of Alice’s illness, Harry’s death, and her coming evening with Jem, unaware that he is a key suspect in Harry’s murder. Nor does Mary know that an undercover policeman came to Jane Wilson that afternoon and asked her if particular gun belonged to her son. Jane innocently affirmed that the gun in question belonged to Jem, unaware that it was the gun that killed Harry Carson. When policemen arrest Jem Wilson at the foundry, he asks a fellow workman to tell his mother he is in trouble. Jane also finds out from the workman that there is evidence against Jem - he and Harry had quarreled over a woman named Mary Barton. Jane Wilson is furious at Mary and refuses to believe that her son is guilty.
Unaware of Jem’s arrest, Mary goes the Wilsons' house as planned and is shocked when Jane Wilson explodes in anger. Jane explains the situation and her wrath softens at Mary’s pitiful sobbing. Jane asks her to leave but Mary begs to stay. Finally, Jane insists, but sends Mary away with the promise that she may forgive the girl tomorrow. Mary staggers home, feeding a poor immigrant boy on the way. She lies on the floor weeping until she falls asleep. She dreams of her mother but is awakened by a voice asking to be let in. Mary rushes towards the voice, calling out for her mother. However, it turns out to be her long-lost Aunt Esther.
Worker strikes were common in English Industrial towns like Manchester - as the labor unions in the Victorian era were not that strong yet. Therefore, the practice of bringing in factory workers from the surrounding countryside, Ireland, and other parts of Europe was fairly common, especially in case all the local workers had united to strike. Labor strikes resulted from a lack of communication between employers and their employees.
Employers, like the mill owners in Mary Barton, were often battling to remain competitive and felt they had no other recourse than to lower wages. However, the employees, upon seeing their boss' comfortable lifestyles, became understandably frustrated. The deputation in the hotel represents this ongoing communication problem. The weavers feel as though they are not being heard, and therefore, are compelled to send non-verbal messages, which leads to Harry Carson’s death.
Although Carson is selfish and indifferent to the suffering of his fellow man, Gaskell does not condone Harry Carson's murder, as shown by her sympathetic portrayal of his mourning family. She frames his death as a cautionary tale, warning her Victorian readers that a lack of communication and understanding between classes can have dire consequences. Until this point, Gaskell has presented the upper-class characters in the novel negatively. However, she emphasizes the tragedy of Harry's death by offering a more vulnerable depiction of his family. Harry's mother, despite the comforts of her life, becomes another mourning woman who has lost her child - the same fate that Jane Wilson suffered not so long ago.
Alice’s paralytic stroke gives evidence to the lack of health care that existed for poor families. The way she has in-home care is accurate, although her lucid childhood memories are an authorial stretch and not a medical side effect of a stroke. However, there is poetic justice in Alice’s figurative, if not literal journey to her childhood home. She has lived a difficult, but honest life, and upon death, she will be assured an eternal home in heaven, a comforting image for the working class. Alice's character is a foil to characters like Esther and John Barton. Despite the struggles she has faced, Alice holds on tight to her morals, and is then rewarded with a peaceful eternity.
Meanwhile, the new rift between Mary and Jane Wilson destroys the illusion of a loving Ruth-Naomi relationship, but Mary’s attempt to comfort Jem's mother reveals her maturation. Mary has grown up quickly since she discovered her real love for Jem. Her ability to accept her feelings for Jem have opened Mary up and drawn her out of the selfish bubble she had created. Instead of being focused on wealth and stature as Harry's wife, Mary has come to understand the importance of true love and kinship. Despite Jane Wilson's verbal lashing, Mary remains steadfast in her desire to help Jem's family, which also shows that her morals are becoming more and more strongly rooted.