John Thornton, mill-owner in the working-class, industrial northern English town of Milton, devotes all his time to the proper running of his mill and to the safety of his employees during the industrial revolution. Taken out of school when he was 14 as a result of his father's debts and subsequent suicide, Thornton employed himself at a local draper's shop, earning and saving his money so his mother and sister could eat, and their father's debters could be paid off. Now thirty years old and established as the owner and proprietor of Marlborough Mills, as well as a magistrate of Milton, successful, intelligent, business-minded Thornton finds time for only a mother's love while he endeavors to keep his workers from striking.
When the Hales - a privileged, middle-class family from the rural south of England consisting of an ex-clergyman, his wife and daughter - move into Milton, Thornton immediately befriends the ex-parson as he eagerly takes on the role of pupil to Mr. Hale's teacher. Mr. Hale's daughter Margaret is not so easily won over. Thornton and Margaret clash over the rights of the working man, the conditions of the mills in Milton, and the lack of regard the mill-owners seem to have for their employees, as Margaret seems to prefer the company of the workers to that of the owners, particularly Thornton. Thornton, himself, however much he disagrees with Margaret, finds her strikingly beautiful and vastly different from any woman he has ever met, and soon falls in love with her, regardless of her superior social standing. Thornton persists in trying to show Margaret how his strict and sometimes harsh methods in the workplace are in effect for the workers' safety, while Margaret, now close friends with poor, unhealthy Marlborough Mills' workers, insists on thinking the worst of him.