Although Charley Kying (Clark Gable) has owned a casino for 15 years, on one rainy night events and people seem to converge and threaten his family home and second home, his gambling house. After a doctor secretly diagnoses him with a severe heart condition and recommends that if he continues to subject himself to the daily stress of a professional gambler, he hasn't long to live. Later that day he's made to realize that he's been neglecting his faithful wife (Alexis Smith) for years and abdicated his duties as father to his son (Daryl Hickman), who resents his father's unsavory reputation and rebuffs his interest in attending that night's prom. Charley's weakling brother-in-law (Wendell Corey), who sponges off him by freeloading at home and cheating him out of petty cash as croupier, agrees to conspire with rival gamblers to cheat Charley out of thousands. Among the others who add stress to what would seem to be Charley's last night in the casino are a rich former girlfriend (Mary Astor) who proposes they renew their relationship, an old nemesis (Frank Morgan) who's vowing to break the bank at the tables, and an old degenerate gambler and former mentor (Lewis Stone) whose desperation leads him to try to take his own life.