Plot
Margaret Hale (Daniela Denby-Ashe) and her parents Maria (Lesley Manville) and Richard (Tim Pigott-Smith) live in the idyllic town in Helstone in Hampshire. At the wedding of her cousin, Edith, Margaret is approached by Edith's new brother-in-law, Henry Lennox (John Light). Lennox visits Helstone a while later and proposes marriage to Margaret; she refuses him.
Margaret's father, a clergyman, has long harbored doubts about the doctrines of the Church of England and resigns his position rather than attest to orthodox beliefs as his bishop requires. To avoid gossip, the family move to the (fictional) industrial town of Milton, Darkshire, in the north of England. Thanks to his friend, Mr. Bell (Brian Protheroe), Mr. Hale is able to find a house. Giving lessons as a private tutor provides him a modest income. One of his pupils is local mill-owner John Thornton (Richard Armitage), who gets off to a bad start with Margaret when she witnesses him beating a worker whom he has caught smoking in the mill, which endangers all the workers. Gradually, Margaret gets used to Thornton, but his mother Hannah (Sinéad Cusack) and sister Fanny (Jo Joyner) disapprove of her, believing her haughty and alien to the customs of the North. In the meantime, Margaret attempts to do charitable work among the mill workers and comes into contact with Nicholas Higgins (Brendan Coyle) and his daughter, Bessy (Anna Maxwell Martin), who suffers from byssinosis from exposure to the cotton fibres in the mills. When Bessy became ill at Hamper's Mill, her father moved her to Marlborough Mills, Thornton's mill, because the working environment is better there. In a meeting with fellow mill owners, Thornton says he had a wheel for ventilation installed in all of the rooms of his factory in order to maintain a healthier workforce, despite the fact that it costs a great deal of money. The other industrialists had refused to install a wheel because of the expense.
Margaret's mother is falling ill. Mrs. Hale desires to see her son, Frederick (Rupert Evans), before she dies. Frederick, a naval officer, was involved in a mutiny and he cannot return to England without risking his life. However, without telling her father, Margaret writes to her brother in Cádiz, Spain, to tell him that their mother is dying. Margaret calls on the Thorntons to borrow a water mattress for her mother and is trapped there while the mill workers riot during a strike. When the angry mob threatens John's safety as he confronts them after Margaret's goading, Margaret defends him from the rioters and is injured by a thrown stone.
Margaret recovers and returns home, telling nobody about what had happened at the Mill, mainly to protect the health of her mother. When Thornton proposes to her the next day, she scorns him, thinking he believes himself superior because of the difference in their financial circumstances. He denies this and tells her that he is in love with her, but she insists that her actions were not personal.
Meanwhile, Bessy Higgins dies and Thornton stops coming for lessons from Mr. Hale. As a distraction for Mrs. Hale and for herself, Margaret visits the Great Exhibition with her Aunt Shaw (Jane Booker), her cousin Edith and Edith's husband. Margaret meets Thornton at the exhibition, where he is discussing the machinery with a group of gentlemen, all of whom are listening with great respect and admiration for his simple good sense. Margaret is embarrassed to meet Thornton so soon after her rejection but defends him when Henry Lennox, who is also attending the exhibition, tries to belittle him for being in trade. As Margaret observes them together, Henry's sophistication and reliance on fashionable wit and sarcasm compares unfavourably with Thornton's honesty.
When Margaret returns home, her mother has taken a turn for the worse. Margaret's brother arrives just in time to see his mother, and she dies shortly after. While Frederick is in the house, Thornton comes to visit his friend Mr. Hale, but he cannot be allowed in, in case he sees Fred. Thornton interprets this as Margaret refusing to see him. The family's servant, Miss Dixon (Pauline Quirke), bumps into Leonards, a former member of Frederick's crew in Milton town, who offers to split the reward money for Frederick's capture with her. Dixon refuses, informing the Hales; it is decided that Frederick must leave at once, before he is discovered and arrested. He and Margaret are seen together at the railway station by Thornton, who mistakenly assumes that Frederick is Margaret's lover. Leonards spies on him and Margaret at the station, and in the brief scuffle Fred pushes him down the stairs. It is later revealed that he died in hospital. Margaret denies to the police that she was at the station, in order to protect Fred, but Thornton, who is the magistrate and saw her there, is morally tested, but ultimately calls off the impending inquiry for the sake of Margaret.
Thornton gives employment to Higgins who seeks work to care for Boucher's children after his death, and master and hand get along surprisingly well, despite their differences. They come up with a plan to feed the workers cheaply in a communal kitchen, and Thornton comes to a greater understanding with his workers as they share ideas. However, losses faced during the strike have put Thornton's business in trouble, and he is forced to close the mill.
Margaret's father visits Mr. Bell in Oxford, and dies there. With no family to keep her in Milton, Margaret leaves the north to stay with her aunt in London. After a few months living with the Shaws, Margaret visits Helstone with Mr. Bell, and meets the new vicar and his wife. Margaret is disappointed to find Helstone much changed, and realises that she has romanticised and idealised her childhood home, and starts to truly recognise the merits of life in Milton.
As Margaret's godfather, Mr. Bell makes over his significant fortune to her when he finds out that he has a terminal illness and chooses to move to Argentina for the better climate. Margaret hence becomes the owner of Marlborough Mills and John Thornton's landlord. Margaret visits Milton with Henry Lennox, who is now acting as her financial advisor; she speaks with Mrs. Thornton at Malborough Mills, expressing her realisation of Mr. Thornton's true character. Meanwhile, Thornton, having discovered the truth about Fred being Margaret's brother from Higgins, goes south to see Margaret's home town of Helstone. At a railway station halfway between Milton and Helstone, Margaret and Thornton cross paths on their respective return journeys. She proposes a business deal by which the factory can be reopened; after this the two share a kiss. Margaret bids farewell to Henry, and gets on the train "home" to Milton with Thornton.
