Following the collapse of his marriage, TV newswriter Felix Ungar decides to commit suicide in a cheap hotel room and fails. He dejectedly makes his way to the weekly poker game being held at the Riverside Drive apartment of his best friend, Oscar Madison, a divorced sportswriter. Felix accepts an invitation to share the eight room apartment, but his hypochondria and his compulsion for order and cleanliness drive the slovenly Oscar to distraction, and the two men are soon quarreling.