Robert Donat stars as Dr. Andrew Manson in this adaptation of A.J. Cronin's best-selling novel. Manson devotes himself to treating the residents of a poverty-stricken Welsh mining community. Tuberculosis runs rampant in the village, and Manson is determined to help stem its tide and bring good health back to people who desperately need it. Through a series of unforeseen circumstances, Manson eventually leaves the community and begins working out of London, where he looks after wealthy hypochondriacs who don't really need his services but are willing to pay from them. While Manson gains money and prestige, he has turned his back on his friends, his wife (Rosalind Russell), and the people who need him most in the process. To give the film a more realistic "English" atmosphere, MGM shot The Citadel at their British studios, although they did import an American director (King Vidor) and leading lady (Russell) for the occasion.