While trying to get his father out of a financial jam, a man comes up with an idea that turns into an unexpected overnight financial fashion success: bottomless pants.
Jack Fine, owner/manager of Fine Fashions of Brooklyn, which solely produces women's dresses, has been having a difficult time the past year due to the company not keeping up with the changing fashions, so Jack is in debt to the tune of $1.5 million to loan shark/gangster Mr. Eddie, a hulking, flamboyant man who has a penchant for picking up and destroying things that bother him. Jack now falls into that category. Instead of figuratively or literally breaking Jack's legs or worse, Mr. Eddie decides to take over Fine Fashions until the debt is paid, naming Jack's son Bobby Fine, an English Literature professor at upstate Chippenango State College, to manage the operations. Not only does this new career, which Bobby has no option but to accept, threaten the possibility of Bobby obtaining this year's tenure track position in the department, but Bobby at the helm of the fashion house threatens to ruin it completely, as Bobby has no idea about fashion whatsoever. Complicating matters is that Bobby and Mr. Eddie's wife, seductive Italian Lira, fall in love at first sight--she doesn't love Mr. Eddie. Bobby's association with Lira accidentally leads to the latest fashion craze which could save Fine Fashions: coined "So Fine", they are jeans which expose the butt cheeks, that area of the pants covered with clear plastic. With Jack and Bobby potentially coming into a financial windfall because of So Fine as well as being the toast of the fashion world, the question becomes whether Bobby will get everything he wants, including the tenure position and Lira, without Mr. Eddie killing him.—Huggo
Bobby Fine (Ryan O'Neal), a Chippenango State College professor, learns from English Department chairman, Dr. Lincoln (Fred Gwynne), that he and Professor McCarthy (David Rounds) are both under consideration for one available tenured position.
In New York City, Bobby's father, Jack Fine (Jack Warden), tries to promote his clothing business, Fine Fashions, but he has lost most of his accounts. Jack also owes $1.5 million to pay off a $250,000 loan from loan shark "Mr. Eddie," (Richard Kiel) who is extremely tall, bulky strong, and violent. Jack cannot pay, so Mr. Eddie declares he is taking Jack's business and insists that Bobby come through with the deal. Jack argues that his son knows nothing about fashion, but Eddie dispatches two thugs to get Bobby.
Meanwhile, Chippenango State College hosts a reception for a renowned poet, whom Bobby greets at the train station. As he drives to campus, Bobby notices a car chasing them, but assumes they are students, until thugs shoot at him. Bobby speeds across campus, carries the poet into the reception, then runs through the cafeteria and is caught by the men. They take Bobby to his father's house, where he learns of Jack's dire situation. Fearing Eddie will kill Jack, Bobby agrees to help his father for a few weeks.
Jack and Bobby go to Mr. Eddie's discotheque, and when they arrive, Eddie is on the dance floor with his Italian wife, Lira (Mariangela Melato). Bobby is immediately attracted to Lira and cannot keep his eyes off her during their meeting. When Eddie returns to the dance floor, Bobby kisses Lira, who admits that she regularly cheats on her husband.
The next day, Bobby works with the staff at Fine Fashions, but the salesmen think he is a snob and everyone realizes he is a klutz.
That evening, while Jack works late romancing a female buyer, Bobby discovers Lira waiting for him outside. She reveals Eddie is working late, and takes Bobby to her home, where he meets her Italian maid, Sylvia (Angela Pietropinto). Lira claims Eddie is not a good lover, then starts to undress Bobby. Meanwhile at a bar arcade, Eddie becomes frustrated playing pinball, rips the machine from the wall, carries it down the street, and smashes the machine outside his home. Inside, Bobby runs upstairs and hides under a bed, while Lira tosses his pants into the fireplace and his shoes into a potted tree. Later, Lira promises Bobby that Eddie is a deep sleeper and when he falls asleep, Bobby can leave. However, when Lira wakens Bobby at 5:00 a.m., she insists they make love and pulls Bobby onto the bed. However, Eddie rolls over, wraps his arms around Bobby and starts to wake up, so Lira knocks her husband unconscious with a pistol, and continues to seduce Bobby.
Later as morning arrives, Bobby wears Lira's sweater, tight jeans and mules as he sneaks outside. He bends over to examine the broken pinball machine and rips two holes in the back of the jeans, exposing his buttocks. Bobby searches a nearby garbage can and finds clear plastic, which he stuffs into his pants to cover the holes. He tries to keep his back from view as he rides a bus, and then walks through the garment district toward his office building.
In the lobby, Bobby runs into several people who recognize him as Jack's son, and think that the daring jeans are Jack's latest design. As the crowd grows, Bobby leads everyone to Fine Fashions so they can place orders for the jeans. Jack is excited, but warns his son that Eddie must never learn of Bobby's rendezvous with Lira. Bobby insists there is no need to worry and the new design will save his father's company. The jeans, bearing a "So Fine" logo and featuring two clear plastic windows in the buttocks area, become a fashion craze. Business booms and Jack wonders if Bobby wants to stay with the business, but Bobby feels he has a commitment to the college. He also wants to distance himself from Lira, who calls several times each day. Jack advises his son to stay away from Lira, and announces that he is repaying Eddie's loan at the end of the week.
A little later, Lira arrives and demands to know why Bobby will not take her phone calls. Bobby admits he is afraid of her husband, but his attraction for her overrides his concern and they make love.
Bobby returns to teaching and, later, Jack heads to Eddie's home to pay off the loan. While Lira and Eddie await Jack's arrival, Eddie stretches his arms, nudges the potted tree, and Bobby's shoe drops in his lap. Lira rushes outside and drives away. Eddie jumps into his car and follows her toward the college campus. Jack arrives and Lira's maid, Sylvia, flirts with him before admitting that Eddie knows about Bobby and his wife. Jack also races toward the campus.
As Bobby eats dinner at a pancake restaurant, Lira runs in, kisses him and admits that Eddie knows the truth. Bobby worries that Eddie might follow her, but Lira insists they can leave for Venice, Italy, in the morning. Bobby takes her to the campus theater for a performance of the opera, Otello. During intermission, Bobby introduces Lira to Lincoln, McCarthy, and their wives. McCarthy pulls Bobby aside, says he forgot their office key, and asks if he can borrow Bobby's.
When Eddie arrives on campus, he learns the location of Bobby's office, breaks down the door and discovers McCarthy having sex with a female student. McCarthy reveals Bobby's whereabouts and Eddie heads for the theater as two security guards arrive. Meanwhile, the lead singer is losing her voice, so Lira rushes backstage and offers to perform the role of "Desdemona." As Lira takes the stage and amazes everyone with her performance, she sees Eddie enter the theater, but continues singing. Eddie locates Bobby and chases him through the audience to the backstage area and up to the catwalk. Bobby grabs a rope and lowers himself to the stage, inadvertently changing the backdrop to Yankee stadium. Bobby hides under the bed onstage while Eddie rushes to the lead actor's dressing room, knocks him unconscious, and dresses in his costume. Jack arrives as Eddie bursts onstage and stuns the audience with his singing. However, as Eddie and Lira continue performing, they change the Italian lyrics to reflect their actual situation, with Eddie promising to kill her. Eddie tosses Lira onto the bed and Bobby jumps out to help her, but is knocked down by Eddie. As Eddie smothers his wife with a pillow, Jack swings on a rope from the catwalk and knocks Eddie unconscious. Lira, Bobby and Jack receive a standing ovation as Eddie is led away by police. Lincoln informs Bobby that McCarthy was caught with a coed and, therefore, Bobby gets the tenured position.
Later, as Bobby and Lira ride in a gondola through the canals of Venice, Italy, Bobby looks over the annulment papers ending Lira and Eddie's marriage, and she agrees to be his wife. In the gondola behind them, Jack cruises with Sylvia, his newfound love.