Randle Mc Murphy (Nicholson) is an incorrigible convict who acts crazy, believing he'll do easier time in a mental hospital than a prison. Getting his wish, on arrival he immediately disrupts the routine imposed by head nurse Ratched (Fletcher), which begins a power struggle for the damaged hearts and minds of the inmates. In McMurphy's crusade, the loons (including Brad Dourif, Danny DeVito, Christopher Lloyd, and William Redfield) awaken from their stupors and regain a measure of vitality, but the powers-that-be see this as insurrection — one they stem by targeting its leader.
Forman's bravura filming of Ken Kesey's book stands as Nicholson's peak. It seems incredible Kirk Douglas wanted to do the part years before (his son Michael actually produced the film), since it's hard to imagine anyone but Nicholson as McMurphy. All the inmate performances are first-rate, including Will Sampson as "Chief," the silent Indian giant who plays a pivotal role in McMurphy's oddball odyssey. A brilliant film.