Fleeing the Irish Republican paymasters for whom he committed murder and mayhem, Henry Smart has left his wife and infant daughter in Dublin and is off to start a new life. When he lands in America, it is 1924 and New York City is the center of the universe. Henry turns to hawking cheap hooch on the Lower East Side, only to catch the attention of the mobsters who run the district.

In Chicago, Henry finds a newer America alive with wild, happy music played by a man with a trumpet and bleeding lips called Louis Armstrong. But in a city also owned by the mob, Armstrong is a prisoner of his color. He needs a man--a white man--and the man he chooses is Henry Smart.