This charming and expensively made historical romance was one of Marion Davies' best films. She spends much of the picture disguised as a boy, something she also did effectively in several other films. A young Irish lad, Patrick O'Day (Stephen Carr), inherits a fortune, providing he travels to New York to claim it within a certain period of time. His father, John (J.M. Kerrigan), manages to scrape together the money to send himself, his son, and daughter, Patricia (Davies), across the Atlantic. But the boy is sick and dies en route to New York. In order to get the money, John convinces Patricia to disguise herself as her brother. They arrive just in time to claim the inheritance, which frustrates cousin Larry Delevan (Harrison Ford), who would have received it had Pat not shown up. Although Delevan is not thrilled with his cousin's arrival, they become fast friends anyhow, and he never suspects that Pat is really a girl. Delevan wants to invest in Robert Fulton's steamship, the <I>Clermont</I>, and Pat loans him the money. But Delevan then wagers on a fight between Bully Boy Brewster (Harry Watson) and the Hoboken Terror (Louis Wolheim). The match is an uneven one and it looks like Delevan will lose all his money, so Pat rings a false alarm to break up the fight. When her deed is discovered, the mob drags her out to be whipped. She takes it for a few lashes before revealing that she's really a girl. Delevan falls in love with her and they marry. Contrary to popular belief, many of Marion Davies' films made money, and Little Old New York was one of them.