Leonardo DiCaprio stars in this movie about New York City during the late 1800s when gangs ran the city, from its politicians to its businesses. While much of the film takes place during the American Civil War, its primary focus is the criminals whose main concern was running the city. The movie captures two rival gangs: the newly arrived Irish-Americans and the "native" New Yorkers. The film opens with a bloody fight between the two groups. DiCaprio plays an up-and-coming Irish-American who gets in with the rival gang, headed by Daniel Day-Lewis. He also becomes romantically involved with a young female outlaw played by Cameron Diaz. The film documents this gang life through the eyes of DiCaprio’s character and follows the conflict until, finally, it comes to a head.