Nice guy John Plummer is engaged to the charming but scatterbrained Elaine Warner, portrayed by Leslie Mann, and has grand plans to use his life savings of $30,000 for a down payment on their future home. This choice stems from his desire not to accept financial help from her affluent father, Mr. Warner (Dennis Farina), who already looks down on John and believes he is unworthy of his daughter. Adding to John's troubles is Mr. Warner's aggressive dog, Rex, who harbors a strong dislike for John and seems to always be on his master's side.
Complicating matters further, John's niece Noreen (Tammy Blanchard), the daughter of his "trailer-trash" sister, Patty (Megan Mullally), has received acceptance into Harvard University. However, she faces a financial hurdle, needing an additional $30,000 beyond her scholarships. Noreen reminds John of a promise he made in the past, captured on a nostalgic videotape, where he vowed to support her educational dreams. Caught in a moral and financial nexus, John grapples with letting down both his fiancée and his niece, a dilemma that highlights his struggle between personal ambition and familial loyalty.
Enter Walter "Duff" Duffy, John's eccentric best friend from high school, who recalls his days of being bullied and is now a struggling landscaper. Duff suggests a daring yet questionable scheme—he claims that a wealthy homeowner keeps large amounts of cash in an unsecured safe, a tempting opportunity that lures John's reluctant agreement. As they plot to steal, Duff backs out at the last minute, leaving John in a precarious situation. He finds himself face-to-face with the homeowner, Honorable Emmett Cook (Richard Jenkins), and the encounter takes a bizarre turn when John is coerced into cross-dressing and playing the part of Cook's deceased wife.
During this outrageous scenario, Cook reveals his emotional turmoil about losing his wife and explains, > “I’m not gay, I just miss my wife.” Eventually, John escapes, but not without Mr. Warner catching wind of his erratic behavior, mistakenly believing he has evidence of John's infidelity.
The misadventures continue as John and Duff hatch a plan to rob a liquor store and later concoct a scheme to deceive a drug lord by claiming to run an ecstasy operation. Throughout their escapades, a cunning police detective (John C. McGinley) edges closer to nabbing them, but lacks the concrete proof to take action.
In a surprising twist, Mr. Warner breaks into Cook's home seeking evidence against John, only to find himself in a similar predicament as he is also forced to "spoon" with Cook. Meanwhile, John's secrets unravel when he is finally confronted by Elaine about the incriminating photo taken of him in drag. To his surprise, Elaine admires his desperate lengths to provide for her and support his niece.
With a newfound alliance, Elaine reveals that her father keeps significant cash at his business, and together with John and Duff, they attempt to execute a robbery. Chaos ensues when Mr. Warner’s dog Rex is inadvertently locked inside the vault, leading to a comical yet frantic scene as Rex chases Duff around in a madcap attempt to escape.
As police sirens blare, John and Elaine make a dash for freedom, but their plans come crashing down as they face charges that include breaking and entering and animal cruelty. However, fortune smiles upon them when the judge in charge of their case happens to be none other than Emmett Cook.
Nervously, John writes a message to Cook, threatening to expose the judge’s peculiar habit, prompting Cook to swiftly dismiss all charges against him. Ultimately, with Duff redeeming himself and donating his life savings, John takes a gamble on a longshot horse—leading to a financial windfall that saves the day. In a joyous climax, John marries Elaine amid a gathering of friends and family, including Mr. Warner, Patty, Cook, and Duff. As Noreen embarks on her academic journey, the last scene humorously reveals Duff contemplating a new venture, offering to "spoon" with Cook for a cool thousand dollars.
