On a rainy London night, the crowds are leaving the opera at Covent Garden. Freddy Eynsford-Hill runs into flower girl Eliza Doolittle, spilling her flowers onto the muddy ground. While she is dressing him down for his clumsiness, phonetics expert Professor Henry Higgins, takes notes regarding her thick, cockney accent. Higgins attracts the attention of another linguist, Colonel Pickering. Since each has been seeking an opportunity to meet the other, it is agreed that Pickering will come to stay with Higgins.
Eliza, having saved a bit of money, comes to Higgins’s home in hopes of engaging his services for speaking lessons. Her accent is so dreadful that Higgins sees a challenge and accepts a wager with Pickering that he can teach her sufficiently to pass her off as royalty. Higgins takes Eliza into his home and the arduous refinement begins.
Alfred Doolittle learns of his daughter’s good fortune and shows up at the Higgins residence. He is not an outraged father demanding that his daughter be brought to him, he wants only compensation of a five-pound note, no more, no less. Higgins is amused at his moral reasoning and pays him off.
Higgins grills Eliza mercilessly. Finally, progress can be seen and Higgins decides to give her a brief “trial run” at the Ascot races.
The now-beautiful Eliza immediately wins Freddy’s heart and does quite nicely with her slow, measured speech. That is, until the races begin. The more excited she gets, the more she slips back into her cockney argot and finally shocks several of the ladies into a graceful faint with some encouragement shouted at her horse: “Move yer arse!”
Six weeks later, despite the setback, Higgins decides that Eliza is ready for the Embassy Ball. Eliza charms everyone quite completely, including the queen and the nefarious linguist, Zoltan Karpathy. After the ball, Higgins and Pickering congratulate each other profusely, but not a word of compliment is spent on the heartbroken Eliza, who confronts Higgins about his lack of caring. He dismisses her with his usual coldness.
Upon leaving, Eliza finds Freddy seated on the front steps of Higgins’s house, and he professes his love for her. She tells him in no uncertain terms how tired she is of words. “If you’re in love,” she sings, “show me!”
Eliza returns to her familiar Covent Garden. There, she finds her father being treated as royalty by pub proprietor and friends alike. Higgins’s recommendation of Doolittle as the most original moralist in England has led to a fantastic monetary windfall. Since he is now “respectable,” his lady friend demands that he marry her.
Higgins learns that Eliza has left and becomes desperate to find her. Finally, he locates her at his mother’s home. Mrs. Higgins has taken a definite liking to Eliza and defends her to her insensitive son. Higgins importunes Eliza to return, asking her if she has ever known him to treat anyone any better than he has treated her. She agrees that he treats everyone equally badly, and, unconvinced that he can ever change, she leaves.
That same evening, Higgins realizes how much he misses Eliza. As he listens wistfully to the recording of their first meeting in his home, Eliza steps into the room, lifts the arm from the machine, and recites the next sentence in her former cockney accent. “I washed me face and hands before I came, I did.”
She has returned.