In the summer of 1963 Brooklyn, New York, 18-year-old Jeffrey Willis (Matt Dillon) is invited to spend the Fourth of July at the exclusive El Flamingo Beach Club in Far Rockaway, Long Island, New York. Steve Dawkins (Brian McNamara) and Henry "Hawk" Ganz (Fisher Stevens), two friends who used to live in the neighborhood whose families are now members of the El Flamingo, need a third player for a gin rummy game at the club. Jeffrey, who is a whiz at math and cards, helps them win $89.90 in a penny-a-point gin rummy game. Jeffrey is impressed by the luxurious club and is smitten upon meeting the beautiful, blonde Carla Samson (Janet Jones) from California who is staying the summer with her relatives, the wealthy Brody family.After the holiday buffet and fireworks, Jeffrey and his friends are leaving when a car stalls in the parking lot. Jeffrey examines the engine and gets the car started. The parking lot attendant offers him a job and puts Jeffrey to work.The next morning, Jeffrey tells his father, plumber Arthur Willis (Hector Elizondo), that he has taken the job. Arthur is upset as he arranged with one of his plumbing clients for Jeffrey to work as an office boy at an engineering firm in Brooklyn. Arthur dreams of his son becoming an engineer, but Jeffrey does not want to spend his summer in an office. Jeffrey places the $40 he made in tips on the table, confident he can contribute to his college tuition, but his father dismisses the gesture, saying that working for tips is not an honest job.That afternoon at the El Flamingo, Jeffrey and other parking attendants watch a high-stakes gin rummy game in which "king" of the game Phil Brody (Richard Crenna), who owns a foreign car dealership, plays against retired Air Force Colonel Cal Eastland (Frank Campanella), who owns the El Flamingo. Jeffrey is impressed by Phil Brody's style and his habit of holding his cards in an upside-down fan pattern. That night, Jeffrey tries to imitate holding cards in the upside-down fan, but cannot master it.Phil Brody's daughter, Joyce (Carole R. Davis), invites Steve Dawkins to dinner at the Brody house, while Joyce's cousin, Carla Samson, invites Jeffrey. Phyllis (Jessica Walter), Phil's snotty wife, is aghast to have a parking lot attendant come for dinner, but Phil Brody takes a shine to Jeffrey after the young man compliments his card playing. Phil teaches Jeffrey some of the finer points of cards, explaining that he does not have a son to share his expertise with. Carla and Jeffrey have a nice evening and share a kiss as he leaves.The next day at the El Flamingo, Phil arranges for Jeffrey to be promoted to cabana boy. Over the next few weeks, Jeffrey makes a lot of money in tips and wins a lot of money in penny-a-point gin rummy games with his friends.One day, Phil Brody takes Jeffrey to his Long Island car dealership, Brody Motors, and lets him drive an Italian-made sports car. Phil tells Jeffrey that he never went to college, but took some night courses at New York University and believes education is not as essential as sales ability, because it is the salesmen of the world who make the money. Phil believes Jeffrey would make a good salesman and will give Jeffrey a job whenever he wants one.Jeffrey, who has been accepted at the Pratt Institute for the fall semester and is on the waiting list for Columbia University, tells his family that he has decided not to go to college and repeats things that Phil said about salesmen making the most money. Arthur Willis, strongly disapproves of Jeffrey's decision because he believes that his dream is for his children to be educated, but Jeffrey insists he is going to be a car salesman.The next day, Arthur comes to the club and invites Jeffrey to join the family for a meal at a nice restaurant after his shift ends, but Jeffrey and his friends are going to the horse races in Yonkers. Arthur and Jeffrey argue until Phil steps in, complimenting Arthur on what a fine son he has and advising him to let Jeffrey spend time with his friends.At the horse races, Jeffrey and his friends lose money after betting on a horse that was supposed to be a "sure thing." Afterward at a diner, some guys from the racetrack start a fight with them and police arrest them all. Arthur bails his son out of jail. On the drive home, Jeffrey and his father get into an argument about money. Jeffrey criticizes his father for saving all his money and making them live in a "dump" in Brooklyn. Hearing that, Arthur slaps his son in the face. When he gets home, Jeffrey packs some clothes and says he is moving out. Arthur mocks him, asking if he is going to become a "fast car salesman." Arthur admits that fast things frighten him. He also says that there are two important things in life: "finding out what you do well and finding out what makes you happy". Arthur says "if God is smiling on you, they're both the same thing".Jeffrey sleeps in a cabana at the club and the next day tells Phil Brody he is ready to work for him. Phil offers him a job as a stock boy at his dealership in Yonkers. Jeffrey is distraught as he was expecting to be a car salesman, but Phil explains he has to grow into the position.That night, Jeffrey and Carla go on a date and make love for the first (and only) time on the beach. Carla hopes he can come visit her in Los Angeles where she will attend college. Jeffrey and Carla then say goodbye to each other.On Labor Day, Phil and his team play another high-stakes gin rummy game against Col. Eastland and his team. As usual, Brody is winning, but Jeffrey notices a man named Big Sid observing the game and signaling Brody about Eastland's cards. Big Sid collapses from sunstroke, falling onto Eastland, and both are taken to the hospital. The other members of Eastland's team, Charlie Cooper and Mario Minetta, need a third player and Jeffrey volunteers. Jeffrey plays against Phil and wins several hands. The game goes on for hours and moves inside when it gets dark and Jeffrey continues to win. On the last hand, the men agree to double the stakes. As Phil hesitates about which card to discard, Jeffrey comments that it is not so easy to win without Big Sid there to help him, then puts down the winning hand. Angry at losing, Phil storms away from the card table. Delighted at their windfall, Jeffrey's two teammates give him a share of the winnings. Jeffrey tells them how Phil has been cheating all summer with the help of Big Sid.A little later that evening, Phil comes to congratulate Jeffrey on winning and offers to let him be a salesman at his new dealership in Newport, California, so he can be close to Carla. Jeffrey declines and tells Brody that he told the others about his cheating scam. Jeffrey tells his friends at the beach club goodbye and goes to Larry's Fish House where his family is having dinner. He makes up with Arthur and says he intends to move back home, then gives his father a hug.