Susan, a single mother of two, works as a waitress in a small town. Her son, Henry, is an 11-year-old genius who not only manages the family finances but acts as emotional support for his mother and younger brother. When Henry discovers that the girl next door has a terrible secret, he implores Susan to take matters into her own hands.

Atlantic City at the dawn of Prohibition is a place where the rules don't apply. And the man who runs things -- legally and otherwise -- is the town's treasurer, Enoch "Nucky" Thompson, who is equal parts politician and gangster.