A gang of penny-ante crooks bumbles their way through their shot at the big time.

New York City crime boss Anthony "Baccala" Vestrummo ponders the morning news as television anchor Sander Vanocur describes Baccala's empire and Brooklyn District Attorney Goodman's concerns that unrest among the local crime families may cause a gang war. After Baccala's dutiful wife performs her daily ritual of starting his car to make sure that no one has connected a bomb to the ignition, he drives from his Long Island mansion to his Brooklyn headquarters. Meanwhile, low-level gangster Salvatore "Kid Sally" Palumbo leaves his walk-up apartment as his gun-wielding grandmother, Big Momma Ferrara, warns him to watch himself. At Baccala's office, Sally argues that he wants to move up, prompting Baccala to promise Sally the lucrative job of running an upcoming bicycle race that will feature an Italian team. A short time after Sally jubilantly arranges for a bicycle track to be built inside a small stadium, the Italian bicyclists arrive in New York. One of the cyclists, Mario Trentano, adapts easily to his new surroundings, quickly stealing most of the amenities in his hotel. At a party to welcome the cyclists, Sally's sister Angela meets Mario and is amused when she sees him pocketing hors d'oeuvres and sandwiches. Later, after they walk through the neighborhood together, she gives Mario a token for the subway, but as soon as she leaves, he hails a taxi. On the day of the bicycle race, the entire Italian-American community joins in the festivities, but the stadium crowd turns hostile when they discover that the bicycle track has not been completed and, consequently, the race must be cancelled. Having failed in his big chance, Sally is demoted by Baccala, who berates him for his incompetence. After the other cyclists return to Italy, Mario, who wants to stay in New York, is forced out of his hotel, so Angela finds him an inexpensive, ramshackle room to rent. Some time later, Sally and his cohorts decide to execute a plan that Big Momma has suggested to assassinate Baccala. The first stage is to kill Baccala's bodyguard, Francis "Water Buffalo" Cosanto, but this fails when Sally's men accidentally shoot Water Buffalo's tire instead of him, then lose him when he escapes into a junk yard. That night, the men who failed their assignment boast that they completed the job, but later, Water Buffalo hits the men with his car, causing them to fall into Sally's basement, which houses the lion Sally adopted when he bought old circus cages to use as starting gates for the cyclists. Meanwhile, Mario steals a priest's suit from an ecclesiastical tailor and asks Dominic Laviano, a friend of Baccala, for money for poor Italian children. Thinking that Mario is, indeed, a priest, Laviano gives him Baccala's name and telephone number, saying that his friend that will contribute generously. After other attempts to murder Baccala and take over his mob turn out badly, Sally decides to use his lion to frighten some of the local merchants into paying him protection money. His tactics work, until he accidentally feeds the lion the bag of money he has collected instead of a bag of steaks. With gangland violence increasing, the frustrated mayor insists that Goodman do something to stop it. Goodman, in turn, has inspector Cornelius Gallagher arrest Sally and his family, hoping to get information. The police learn nothing, but decide that the pretty Angela, who is an NYU student, might be intriguing to the press. Upset and frightened when reporters follow her, Angela goes to Mario's place, where they make love. Later, Angela asks Mario to come to dinner at her house, where Big Jelly Catalano, one of Sally's henchmen, remembers having seen Mario dressed as a priest. Certain that Mario not only is a con man but has taken Angela's virginity, Big Momma is about to cut off his fingers when he produces Baccala's telephone number and says that Laviano has arranged a meeting. Sally now senses a golden opportunity, and Big Momma outlines a plan whereby Sally can kill Baccala while he is talking with Mario. Soon Mario has his meeting with Baccala and arrives at the designated restaurant in his clerical suit. Outside, Sally, Big Jelly and their cohort, Beppo the dwarf, are holding Water Buffalo prisoner and waiting for their chance to enter the restaurant. Aided by the bartender, who gives Baccala's men "mickeys," Sally walks into the restaurant and fires at point blank range, but the gun, which Big Jelly has fitted with the wrong caliber of bullets, blows up in Sally's hand, leaving Baccala unscathed. Thinking that he has been saved by a miracle, Baccala is overjoyed with Mario and promises him money. Sally and the others quickly get away in their van, and when the police arrive, Baccala and the others deny that they know or saw anything. Later, Sally tries to feed Water Buffalo to the lion, but Water Buffalo dies of a heart attack first, so Sally decides to dump the body off the Verrazzano Bridge. That plan also goes awry when the body lands on a passing tugboat. News of the incident further insenses the mayor and Goodman, who decide to stage a large-scale raid on Sally's office. Delayed because one of the television networks could not arrive on time, the raid finally takes place without bloodshed as Sally and his men casually play cards when Goodman, Gallagher and the police arrive and arrest the entire Palumbo family. Because Goodman has been wearing a gas mask, in case of tear gas, a reporter asks him to restage his entrance without the mask, but Goodman accidentally opens the basement where the lion lives, forcing him to call out to Sally for help. Later, at the police station, Goodman and Gallagher question Mario, who has also been picked up. They threaten him with deportation until Goodman says that if he testifies against Angela before the grand jury, he may stay in the country. Mario agrees, but when he is questioned before the grand jury, Mario pretends not to speak any English, infuriating Goodman. With no evidence against Angela, whom Goodman had hoped to tie to college radicals, she also is released, but not until after a police woman tells her that Mario did not testify against her and, as a consequence, is being deported. Angela then rushes to the airport but is only able to see Mario as he boards a plane for Italy. When she returns home, Angela goes to the basement and lets the lion go. The next morning, after announcing that a lion is at large in Brooklyn, Vanocur reports that Sally and his cohorts have confessed to various crimes and will each be serving a year in jail. After the broadcast, Baccala's wife successfully starts his car, Baccala kisses her goodbye, then shuts the door, causing the car to explode.