The movie starts with a speech by Frank Costello (played by Jack Nicholson), who's talking about the good ol' days in Boston.
During the speech, we see footage of rioting in the streets. Costello basically tells us that he has no interest taking a backseat in life. He wants to be the driver, and he wants to control everything that happens to him.
We see Frank go into a diner or malt shop where he shakes down the owner for "protection" money, which tells us that Frank is a mobster of some kind. He also compliments the guy on his pretty teenage daughter and calls the girl over. When she comes, he makes a rude sexual comment to her.
Frank notices that a young kid down the counter is looking at him. He asks the kid if he belongs to Johnny Sullivan, and the kid nods, since he is Colin Sullivan. Frank knows that the kid's dad is dead, so he buys the kid a ton of groceries and comic books, then tells him that if he ever wants to earn some extra money, he should come see him.
We see the young kid working as an altar boy, then we flash to Frank telling him not to obey what the Church says, because the Church likes to give out orders.
Frank says you need to make your own orders, and we cut to some footage of him killing a mafia guy and his girlfriend because, apparently, the mafia tried to move in on his turf.