Powerful NYC corporate raider Edward Lewis invites his girlfriend Jessica to join him on a business trip. However, weary of being at his constant beck and call, she ends their relationship.
One night, leaving a business party in the Hollywood Hills, Edward takes his lawyer Philip's Lotus Esprit and finds himself in the red-light district on Hollywood Boulevard. There he meets struggling prostitute Vivian Ward.
Lost and struggling to operate the stick-shift, Vivian offers to drive Edward to the Regent Beverly Wilshire Hotel. Impulsively, he hires her for the whole night and, despite initial awkwardness, finds her charming and they have sex in his penthouse suite.
The following day, Edward asks Vivian to stay for the week, as he must attend a series of business events while attempting to acquire Jim Morse's shipbuilding company. After negotiating, Edward and Vivian agree on $3,000. He also gives her money to buy appropriate clothes.
However, when trying to shop on Rodeo Drive, snobbish and rude saleswomen turn Vivian away. She asks the hotel manager Barney for assistance. He gets upscale store saleslady Bridget, who is very kind, to find her a cocktail dress for that evening's business dinner. Later, Barney teaches her table etiquette.
Edward is astounded by Vivian’s transformation. At dinner, he introduces Vivian to Morse and his grandson David, who is to take over the company. The Morses are charmed by her, but ultimately the dinner does not go well as they are unhappy with Edward's plan to dismantle their company.
Edward opens up to the transformed Vivian. He reveals details about his personal and business life, including his estranged relationship with his late father Carter.
When Philip suspects Vivian is a corporate spy, as he sees her talking to David Morse at a polo match, Edward explains their arrangement. The married lawyer later crudely propositions her for her services after Edward leaves. She gets upset with Edward for exposing her in that way. He apologizes, admitting that he was jealous of Vivian talking to David and acknowledging that her directness is having a positive effect on him.
Edward takes Vivian by private jet to see La traviata at the San Francisco Opera, a story about a prostitute who falls in love with a wealthy man. She is moved, and she breaks her "no kissing" rule before having sex with him. Believing Edward has fallen asleep, Vivian says she loves him.
As the week is almost finished, Edward offers to get Vivian a condominium and an allowance, promising to visit her regularly. However, Vivian is offended, feeling he is now treating her like a prostitute. She tells her childhood fantasy of being rescued by a knight on a white steed.
Edward meets with Morse but, influenced by Vivian, chooses to work with him to save his company instead of dismantling it. Meanwhile Philip, furious that Edward's new direction has cost him a fortune, goes to the Beverly Wilshire to confront him. However, he finds Vivian. So, blaming her for Edward's changes and angry at his business decision, Philip hits her and attempts to rape her. Edward arrives, pulls Philip off of Vivian, punches and fires him.
After completing his business in Los Angeles, Edward asks Vivian to stay with him for one more night, but only if she wants to, not because he is paying her. She gently refuses and leaves after telling him she thinks he has "lots of special gifts."
Vivian returns to her apartment hotel to pack for her move to San Francisco to get a new job and finish her high school degree. She gives her roommate, fellow prostitute Kity De Luca, some money and tells her she has "a lot of potential." Kit leaves sex work and enrolls in beauty classes. Vivian then waits in her apartment for the bus.
Vivian's rejection prompts Edward to re-evaluate his life, so he reroutes the chauffeur to her apartment instead of the airport. He climbs out of the white limousine's sunroof and ascends the fire escape to 'rescue' Vivian, just like the knight in her childhood fantasy. When he asks her what happens after the knight saves her, she responds "She saves him right back", and kisses him.
