McMurphy (Jack Nicholson) escapes work on a prison farm by feigning mental illness, but he finds himself in a far more coercive institution than the one he left behind. The other men, both sane and insane, are just like him: they hide in the locked ward from the law, their families, or the despair of their own lives.
McMurphy animates the dull monotony with fractious games, pranks, and excursions, but he encounters stiff opposition from the head nurse, Mildred Ratched (Louise Fletcher), whose system provides her with pills and electroshock to maintain control. When the nurse discovers that McMurphy has smuggled two women into the ward, she threatens to tell the mother of young Billy (Brad Dourif). Billy commits suicide and an enraged McMurphy tries to strangle Ratched. McMurphy is lobotomized and returned to the ward only to be smothered by his friend Bromden, who then escapes.
Warren Schmidt, played by Jack Nicholson, is a middle level officer in an Omaha insurance company who faces retirement and, shortly afterward, the sudden death of his wife of 42 years. He struggles with emotional chaos and mental confusion and with the nagging thought that his life is over and that he has failed to make the world better in any way.
An additional complication is that his only child, Jeannie (Hope Davis), is planning to marry a man (Randall, played by Dermott Mulroney) Schmidt strongly feels is below her. He tries several times to prevent the marriage but fails at that, too. Returning home from the wedding in despair, Schmidt finds a piece of mail with a drawing made by a young boy in Tanzania he had begun to support just after he retired, and the final scene shows him deeply moved.
The devoted, and antagonistic, bond between a dramatic, charismatic widow (Shirley MacLaine) and her quietly rebellious daughter (Debra Winger) is the focal point of this film's exploration of a range of human relationships and their changes over time and under various pressures, including that of serious illness. The major focus of the last part of the film is the illness and death of the daughter from cancer and its impact on her mother, her husband and children, and their immediate circle of friends and lovers.
