On Staten Island, New York, photographer Monty Capuletti documents a little girl’s fifth birthday. While entertaining the child, three marijuana cigarettes fall out of a hand puppet, and Monty fumbles for an excuse. At his home office, Monty sorts through the debris on his desk, which includes partially eaten food, parking tickets, date books, liquor, and drugs. Elsewhere in New York City, Monty’s mother-in-law, Mrs. Kathleen Monahan, conducts a business meeting with her nephew, Clive Barlow, at Monahan’s, the department store she inherited from her late husband. The agenda includes firing the cleaning staff, reneging on a charitable donation, and spending the weekend at the Capuletti home for the wedding of Mrs. Monahan's granddaughter, Allison. Mrs. Monahan and her nephew arrive the day before the wedding, and Monty is forced to endure her insults until his friend, plumber Nicky Cerone, appears with his utility van. As Nicky drives to the bakery to pick up Allison’s wedding cake, Monty bemoans Mrs. Monahan’s disapproval of his vices, but also admits he has no self-control. Once the enormous cake is placed inside the van, Monty and Nicky invite their friends, Louie, the bartender, and Paddy, to join them at the racetrack where they place a large bet on a horse. When the jockey intentionally causes the horse to lose, Nicky leaps onto the track and beats him with his own riding crop. That evening, Nicky attacks the bartender at a strip club for insulting his plumbing skills. Meanwhile, at the Capuletti home, Monty’s wife, Rose, tells Allison of her father’s warmth and sensitivity, unaware that elsewhere, an intoxicated Monty is losing another large sum of money in a crap game. Nicky smokes marijuana as he drives Monty home, and destroys the wedding cake when he drives the van into a wall. Allison is married the next morning in a Catholic church, followed by a crowded reception in the tiny back yard of the Capuletti home. Repulsed by his new son-in-law, a gangster named Julio, Monty welcomes him to the family only after being prodded by Nicky. The newlyweds leave for their honeymoon in a “lowrider,” and Julio anticipates a night of lovemaking, unaware that Allison is a steadfast virgin. Upon reaching their destination, Allison is offended by Julio’s advances and returns to her parents’ home. Later that week, Monty is contacted by attorney Daniel Scrappleton, informing him that Mrs. Monahan died in an airplane crash. Rose is to receive the bulk of the estate, including the department store, providing Monty is able, over the course of a year, to abstain from all vice and keep his weight under 175 pounds. If Monty fails, Clive will be the beneficiary. Monty agrees to the terms, convinced by his younger daughter, Belinda, that Rose deserves the inheritance. Under Belinda’s watchful eye, Monty stays on his diet, exercises regularly, and abstains from his vices, despite Clive’s repeated efforts to sabotage him. One night, Julio attempts to reconcile with Allison by making an impassioned speech from the Capuletti’s front yard, prompted by his friend, Hector, who is obscured by foliage. The two men start to bicker, and Allison, Belinda, and Rose stare in bemusement as Julio appears to argue with a shrub. On another occasion, Julio and Hector attempt to enter the house through the second-story bathroom, but are thwarted when Monty heeds the call of nature. As the year wears on, Monty’s nerves are frayed, and during a photography session, he offends the doting parents of an uncooperative child, ruining his reputation in the community. Monty is plagued by insomnia, and when he tells Rose that he is unable to find work, she strengthens his resolve by reminiscing about the night he proposed to her. Hoping to get a new perspective on Rose’s inheritance, Monty and Nicky visit Monahan’s department store, where they are treated with contempt by the staff for their lack of fashion. Following an altercation with a salesclerk, they ask to see Clive, who is in a meeting with his buyers. When Monty and Nicky explain that the men’s clothing offered by Monahan’s is not sufficiently masculine, Clive hires Monty as a fashion consultant, with the intention of humiliating him. Monty creates the “Regular Guy Look,” comprised of loose-fitting shirts and pants, laceless shoes, and white socks. The ensuing fashion show is greeted with derision by the fashion press, compelling Monty to drown his humiliation in alcohol. While leaving for Louie’s bar, Julio approaches the house with a pistol in his hand, intent on reclaiming his wife by force. Monty tackles Julio, who accidentally shoots him in the buttocks. With only a month remaining before the execution of the will, Monty’s five weeks in traction ensure his family of inheriting the Monahan estate. In addition, the “Regular Guy Look” has been embraced by the public, making Monty a fashion icon. The following Christmas, the Capulettis, the Monahans, and their friends celebrate aboard a yacht. Julio is reunited with Allison, although he lacks the stamina to keep up with her insatiable sexual appetite. Scrappleton boards the yacht accompanied by Mrs. Monahan, who announces that she faked her own death as a test of Monty’s will power, and he has won her approval. After moving his family into the opulent Monahan mansion, Monty continues to impress his mother-in-law with his self-control, while keeping her ignorant of his ongoing poker game in the basement, where he shares beer and pizza with Nicky, Paddy, and Louie.