McMurphy(Jack Nicholson), a man with several assault convictions to his name, finds himself in jail once again. This time, the charge is statutory rape when it turns out that his girlfriend had lied about being eighteen, and was, in fact, fifteen (or, as McMurphy puts it, "fifteen going on thirty-five"). Rather than spend his time in jail, he convinces the guards that he's crazy enough to need psychiatric care and is sent to a hospital. He fits in frighteningly well, and his different point of view actually begins to cause some of the patients to progress. He also endures and stands witness to the abuse and degradation of the oppressive Nurse Ratched(Louise Fletcher), who gains superiority and power through the flaws of the other inmates. McMurphy and the other inmates band together to make a rebellious stance against the atrocious Nurse.