A chance meeting outside Covent Garden between Colonel Pickering and Professor Higgins leads to an intriguing wager that Higgins could pass a common flower girl, Eliza Doolittle, as a Duchess at the embassy Ball. Eliza hearing this decides to engage Higgins to teach her to speak properly so that she can improve her station to the heights of a shop assistant. The challenge is too appealing for Higgins and Pickering, and so her education begins.

Her father, Alfred Doolittle, sees the opportunity to profit from his daughter's strange liaison with these two gentlemen and visits Higgins' house. His demands for five pounds compensation is met and Higgins is so impressed by Alfred's natural rhetoric and streetwise philosophy he recommends him as a lecturer to an American philanthropist.

Eliza's first outing as a lady is at Ascot where all goes well until the excitement of the race leads her to urge her horse on with embarrassing consequences.

The night of the embassy ball is full of apprehension for Eliza, Higgins and Pickering. Will Eliza behave; will the oily Zoltan Karpathy expose her? Eliza is a great success but Higgins and Pickering take all the credit. Eliza, upset, takes refuge with Mrs Higgins, Henry's mother, who has become very fond of her, leaving Pickering and Higgins distraught at her going.

Alfred Doolittle is now a rich man and we see him regarding his forthcoming wedding with mixed feelings. His old cockney friends enjoy his pre-nuptial party and his discomfort.

Happily, as befits this bewitching and romantic story, Henry finds Eliza and despite the differences in their backgrounds they both realise how much they care for each other.