Set in the period from 1846 to 1863, this is the story of how Irish and Italian gangs (and subsequently, the Mafia) got started in New York City in that time of Tammany Hall and Boss Tweed. The two gangs at the heart of this film are the Dead Rabbits and the Native Americans. Amsterdam Vallon (DiCaprio) is the son of the Rabbits' murdered leader, and he vows vengeance on the man who killed him, Bill "The Butcher" Poole. Cameron Diaz plays a thief that falls in love with Vallon.