In 1963 Oregon, Randle Patrick “Mac” McMurphy (Jack Nicholson), a recidivist anti-authoritarian criminal serving a short sentence on a prison farm for statutory rape of a 15-year-old girl, is transferred to a mental institution for evaluation. Although he does not show any overt signs of mental illness, he hopes to avoid hard labor and serve the rest of his sentence in a more relaxed hospital environment.
McMurphy’s ward is run by steely, unyielding Nurse Mildred Ratched (Louise Fletcher), who employs subtle humiliation, unpleasant medical treatments and a mind-numbing daily routine to suppress the patients. McMurphy finds that they are more fearful of Ratched than they are focused on becoming functional in the outside world. McMurphy establishes himself immediately as the leader; his fellow patients include Billy Bibbit (Brad Dourif), a nervous, stuttering young man; Charlie Cheswick (Sydney Lassick), a man disposed to childish fits of temper; Martini (Danny DeVito), who is delusional; Dale Harding (William Redfield), a high-strung, well-educated paranoid; Max Taber (Christopher Lloyd), who is belligerent and profane; Jim Sefelt (William Duell), who is epileptic; and “Chief” Bromden (Will Sampson), a silent American Indian of imposing stature believed to be deaf and mute.