After going through agonizing withdrawal and joining Alcoholics Anonymous, Joe Clay (Jack Lemmon) quits drinking. He manages to get a job and a small apartment and starts being a good father to his daughter again.
But Joe's wife Kirsten (Lee Remick), who never drank before she met Joe, remains an alcoholic. She visits Joe at his apartment, and tries to get him to return to drinking with her. Joe refuses, and watches sadly as Kirsten leaves and heads into a nearby bar for a drink.
Joe comforts his daughter, and reassures her that one day, Kirsten will stop drinking as Joe did.
Thanks John L!