Is it Risky Business, Maybe?

High-achieving high school student Joel Goodson lives with his wealthy parents in the Chicago North Shore area of Glencoe. His father wants him to attend Princeton University, his alma mater, so Joel participates in Future Enterprisers, an extracurricular activity in which students work in teams to create small businesses. When Joel's parents go away on a trip, his friend Miles convinces him to use his newfound freedom to have some fun. On the first night, Joel raids the liquor cabinet, plays the stereo loudly, and dances around the living room in his briefs and button-down shirt to "Old Time Rock and Roll".

The following day, Miles calls a prostitute named Jackie on Joel's behalf. Jackie turns out to be a male cross-dresser, so Joel pays him just to leave. But, as he is leaving, he gives Joel the number for another prostitute, Lana. That night, Joel is unable to sleep and hesitantly calls Lana, who is revealed as a gorgeous blonde woman, and they spend the entire night having sex.

The next morning, Lana asks Joel for $300 ($925 in 2023 dollars) for her services. He goes to the bank, but when he returns, she is gone, along with his mother's expensive Steuben glass egg. Joel finds Lana and demands the egg back, but her pimp Guido interrupts them, pulling a gun. While in his father's Porsche 928, Joel is chased by Guido, but eventually escapes. Lana tells Joel that the egg is with the rest of her belongings at Guido's. He lets her stay at his house while he goes to school. When he returns, his friends have come over, and Lana has invited another prostitute, Vicki, to stay, but Joel rejects the idea. The women leave, only to encounter Guido and get into an altercation on Joel's front lawn before running back into his house. Joel agrees to the women spending one more night.

Later that night, Joel, Lana, Vicki, and Joel's friend Barry go out and get high on marijuana. After Lana accidentally bumps the Porsche out of gear while retrieving her purse, the car rolls down the hill and onto a pier (despite Joel's desperate attempt to stop it); the pier collapses, and the Porsche sinks into Lake Michigan. When Joel takes the car to a repair shop, he is horrified to learn how much fixing it will cost. He and Lana later decide to turn his parents' house into a brothel for a night; Joel's share of the profits will pay for the repairs. The party is hugely successful; the house is packed with Joel's friends and classmates and Lana's co-workers. However, the recruiter from Princeton, Rutherford, chooses that night to interview Joel for admission to Princeton. The interview is plagued by interruptions, and Rutherford is unimpressed by Joel's résumé. Afterwards, he stays at the party and becomes acquainted with Lana's friends. After the party, Joel and Lana have sex on a Chicago "L" train.

The next morning, when Joel comes home after retrieving his father's car from the repair shop, he finds that his house has been burglarized. When he tries to call Lana, Guido answers; he tells him he will let Joel buy back his furniture. Joel and his friends manage to get everything moved back in just as his parents walk in, though his mother notices a crack in her egg. Later, Joel's father congratulates him; the interviewer was very impressed, and Joel will be accepted into Princeton.

Joel meets Lana at a restaurant, and they speculate about their future. She tells him that she wants to keep on seeing him; he jokes that it will cost her.