King of the Underworld is a 1939 American crime drama film starring Humphrey Bogart as a gangster and Kay Francis as a doctor forced to treat him.

Joe Gurney, the patient's boss, gives Niles $500 as a reward, and suggests he take his "million dollar hands" uptown, where he can treat the rich.

Though the district attorney has no case, he charges Carole with being guilty of being married to Niles just to put on a good show for the public.

She relocates with her Aunt Josephine to a town, Wayne Center, where two of Joe's men have been jailed, hoping to get in touch with the gangster.

He and his amateur gang initially suspects nearby wanderer Bill Stevens of having shot at him, but then a nail is extracted from the tire.

When Bill mentions that he has written a book about the mistakes that brought about Napoleon's downfall, Joe becomes very interested, as he is a great admirer of the French dictator.

When she is warned that the sheriff and government men are coming to arrest her (a $100 bill Joe gave her was traced to a robbery), she devises a plan.

She returns to Joe's hideout and tells him he has a serious infection, one that will make him go blind in six hours unless it is treated immediately with eye drops.