Lucas Marsh (Robert Mitchum) is a brilliant and dedicated medical student who has aspired to be a doctor since childhood. His mother is dead and he is estranged from his alcoholic father, who has squandered the family's money, leaving Lucas unable to pay for medical school. In order to get the needed tuition money, Lucas marries an older nurse, Kristina "Kris" Hedvigson (Olivia de Havilland), who has substantial savings. Although Kris loves Lucas and helps him in a variety of ways, he is indifferent towards her and considers her "stupid" though she is an excellent nurse. Lucas cares only about doing excellent medical work, and frequently clashes with other doctors he considers incompetent, including his wealthy best friend Alfred Boone (Frank Sinatra). Kris, Alfred, and Lucas' mentor Dr. Aarons (Broderick Crawford) try to humanize him and teach him that all doctors sometimes make mistakes.