Kevin Franklin, a native of inner-city Pittsburgh, has spent his life dreaming of wealth and success despite being raised in an orphanage. As a young man, he fantasized about driving a sleek Porsche and living the high life, but reality has been quite different. Now in his mid-50s, Kevin drives a battered MG Midget, and his efforts to become rich are limited to a string of unsuccessful get-rich-quick schemes. He has racked up a significant debt, with a $5,000 loan from loan sharks ballooning to $50,000 due to interest and penalties, forcing him to contemplate fleeing the city, especially when he considers leaving via Pittsburgh International Airport.
One day, fate takes an unexpected turn when Kevin overhears a conversation at a local diner between Phil Hartman, playing lawyer Gary Young, and his children. They are waiting to pick up a man named Derek Bond, who is Kevin’s childhood friend. Gary mentions he has not seen Derek in twenty-five years and doesn’t know what he looks like. Seizing this opportunity, Kevin discreetly gives his baseball cap to the real Derek to throw off a pair of clueless mobsters who are after him and then impersonates Derek himself. He confidently introduces himself as Derek Bond to Gary's family, who, unaware of the deception, invite him into their luxurious home in Sewickley.
Despite knowing little about dentistry, Kevin manages to convincingly deceive those around him that he is Derek Bond, a successful dentist. His friendly and charming personality quickly makes him a favorite among Gary’s butler-like wife Emily, Kim Greist, and the rest of the affluent household. Gary, played by Jeffrey Jones, is a busy lawyer who is often preoccupied with his demanding career and his family. His wife Emily runs a rapidly growing chain of frozen yogurt shops, which adds to the strain on their marriage, especially as her business ventures put her at odds with a rival yogurt company—one that is owned by her competitor. The tension is further compounded by Gary’s work environment, where his arrogant and bigoted boss creates a hostile atmosphere.
The story explores the growing bond between Kevin and Gary’s daughter Brooke, a goth teenager played by Wynonna Smith, as Kevin encourages her to stand up to her dishonest boyfriend. He also strikes a rapport with Jason, Gary’s young son played by [Chauncey Leopardi], who dreams of becoming a pro basketball player. Over time, Kevin’s influence helps Gary find the courage to stand up to his oppressive boss and ultimately leave his law firm to focus more on his family’s happiness.
Meanwhile, the mobsters chasing Kevin threaten his loyal friend Larry, played by [Stan Shaw], into revealing Kevin’s whereabouts. Reluctantly, Larry agrees to pick him up, but their confrontation sparks tensions as Kevin criticizes Larry for not appreciating friendship. This confrontation leads Kevin to realize that Gary, the man he has been impersonating, has actually been his true friend all along. When Kevin returns to the Youngs’ house, he finds the mobsters have taken Gary’s family hostage, leading to a tense and dangerous showdown. The truth about Kevin’s identity is finally unveiled when the real Derek Bond shows up on the scene.
Kevin’s escape from the mobsters involves a chaotic and humorous chase through a charity marathon, where he manages to lose his pursuers. During this ordeal, Gary, surprisingly, decides to help Kevin despite his deception, motivated by a desire to bring his fractured family closer together. Kevin confesses that he bought an instant lottery ticket the day before, claiming a chance at winning a $1 million prize on a Saturday night TV show. However, he ultimately sacrifices his chance at the jackpot to pay off his debt, handing over the ticket to the mobsters.
The film concludes with an uplifting note as it fast-forwards to winter, showing Kevin in a shiny red Porsche, parked in front of the Youngs’ house with Larry. Kevin is now a successful author, hosting a promotional party for his new book, Handbook for Houseguests, which is based on his chaotic yet heartwarming experiences with Gary’s family. The gathering watches eagerly as the mobsters spin a wheel, initially landing on the million-dollar jackpot but finally settling on $5,000—a victory that brings Kevin joy and the mafia’s disappointment. During the closing credits, Gary and Kevin entertain the crowd with a playful medley of Christmas-themed food parodies, as they prepare a barbecue in the Youngs’ backyard, celebrating their newfound friendship and the holiday spirit.
