Spencer Tracy stars in John Ford's sentimental adaptation of Edwin O'Connor's novel about the final campaign of a big city mayor, loosely based upon the life of Boston politician James Curley. Tracy is Frank Skeffington, the political boss of an Eastern city dominated by Irish-Americans. Skeffington tries to assist the people of the city and avoids cutting political deals with the power elite. But despite his concern for the people, Skeffington has no friends, just flunkies. The Mayor is greatly admired by his idealistic nephew Adam Caulfield (Jeffrey Hunter), who writes for an opposition newspaper run by Amos Force (John Carradine). When Skeffington needs money for a loan, he asks the powerful banker Norman Cass (Basil Rathbone), but Cass steadfastly refuses. In retaliation, Skeffington appoints Cass's retarded son as an interim fire commissioner. To prevent his son from disgracing the family, Cass agrees to the bank loan. But Cass uses his deep pockets to finance the opposition's candidate for mayor.