Edward Lewis, a high-powered corporate raider from New York, buys and dismantles struggling companies, selling off the assets for profit. He wants his girlfriend Jessica to accompany him during a business trip, but fed up with being his "beck and call girl", she breaks up with him. Leaving a business party in the Hollywood Hills, Edward takes his lawyer's Lotus Esprit sports car and accidentally ends up on Hollywood Boulevard in the city's red-light district. There he encounters sex worker Vivian Ward. As he is having difficulties driving a manual transmission car, he pays Vivian to drive him to the Regent Beverly Wilshire Hotel. Edward then impulsively hires her for the night, and despite some awkwardness, finds her charming and has sex with her.

The next day, Edward asks Vivian to play his girlfriend that week at a series of business events he is attending while attempting a takeover of shipbuilder James Morse's company. Edward offers Vivian $3,000 and a new wardrobe for six days. Vivian excitedly accepts, but when she attempts to go shopping on Rodeo Drive, she is turned away by the rude, snobbish saleswomen and turns to Barney, the hotel's manager, for help. He teaches her proper etiquette and arranges for her to buy a cocktail dress for an important business dinner that evening. At the dinner meeting Edward introduces Vivian to James and his grandson David; the latter is being groomed to take over the company after his grandfather dies. The business meeting does not go well and James and David are unimpressed by Edward wanting to buy and sell off their company. Edward is impressed by Vivian's transformation and opens up to her, revealing details about his personal and business life, including his turbulent relationship with his late father, Carter, from whom he was estranged at the time of his death.

When Edward's attorney, Phillip, suspects Vivian is a corporate spy after seeing her talking to David at a polo game, Edward reveals how they met. Phillip later crudely propositions Vivian for her services after Edward is finished with her. Vivian is hurt and furious at Edward for exposing her. Edward apologizes, revealing he was jealous of Vivian talking to David and realizes Vivian's straightforward personality is rubbing off on him. Edward takes Vivian by private jet to see La traviata at the San Francisco Opera. The story of a sex worker who falls in love with a rich man moves Vivian. She later breaks her "no kissing" rule while having sex with Edward. After mistakenly believing Edward is asleep, Vivian admits she loves him.