Late one rainy night in Covent Garden, London, a variety of pedestrians seek shelter under the portico of a church, including a wealthy woman and her daughter, Clara. The mother and daughter are waiting impatiently for Freddy, Clara's brother, to get a taxi. A bystander informs them that there probably won't be any taxis available. Freddy suddenly rushes under the portico and tells the two women that he can't find a single cab.
The rain forces people from a variety of different social classes, who normally don't interact with each other, to come together under the portico. Freddy is fulfilling the role of the chivalrous gentleman, going out into the rain to find a taxi for his sister and mother.
Freddy says he has looked all over for a taxi, but the mother and daughter are insensitive to his efforts and tell him to go look again and not come back until he has found a cab. Freddy protests but then finally goes. As he leaves, he bumps into a flower girl, who calls him Freddy. The mother asks the lower-class flower girl how she knows her son's name.
Here the gender roles are pushed to comedic effect, where Freddy is forced by his mother and sister to be chivalrous even though doing so is pointless: there are no cabs. Freddy's mother is surprised and confused when the lower-class flower girl apparently knows who her (upper-class) son is.
The flower-girl says that she'll tell the mother in exchange for some money. The mother agrees and gives her six-pence. The flower-girl says that she just called the man Freddy because that is how she would refer to any random person she doesn't know. Clara is exasperated at the waste of money. An elderly gentleman comes under the portico for shelter.
The mother's misunderstanding arises from her lack of knowledge of the flower girl's lower-class slang. The gentleman's social standing is instantly identifiable by his dress and appearance.
The flower-girl asks the gentleman to buy a flower, but he says he doesn't have any change. He rummages in his pockets and finally finds some small coins, which he gives to her. A bystander tells the girl to be sure to give the gentleman a flower for the money, because there's someone standing at the back of the portico watching and taking notes.
The interaction between the gentleman and the flower girl makes their positions in the social hierarchy very clear, as she must beg for whatever change he can spare.
The flower-girl worries that she is in trouble but the man taking notes steps forward and asks what the matter is. A bystander tells him the flower-girl thought he was a "copper's nark," (a police informant). The man doesn't understand the slang. He reads his notes, which copy down exactly what the girl said previously in her lower-class dialect.
The bystander misinterprets the note-taking man's appearance, thinking that he is a policeman. Again lack of knowledge about another social group's slang causes confusion. The man is interested in the bystander's and the flower girl's accents and slang.
Some of the bystanders think the man is a policeman and tell him not to worry about the flower-girl. One bystander says the man isn't a cop, but rather a "blooming busybody," and the man asks him how his people at Selsey are. The bystander is shocked that the man knows where he's from. The man then guesses correctly where the flower-girl is from. Still thinking she is in trouble, the flower-girl insists that she is "a good girl."
The bystanders continue to think (wrongly) that the man is a policeman, based on his appearance and behavior. The man is able to guess where everyone is from by their speech, though these guesses smack of a certain condescension, as if by knowing where they are from he thinks he knows who they are. The flower girl insists on what she is: a good girl.
The note-taking man continues to guess where everyone is from, to all the bystanders' surprise. The rain begins to stop and Clara and her mother wonder where Freddy is. The man guesses where both of them are from. He then offers to whistle for a taxi. Clara tells him not to speak to her. As people notice that the rain has stopped, the crowd under the portico disperses.
The man is able to deduce a surprising amount of information about various bystanders based only on their manner of speaking. Clara does not want to speak to him perhaps because she is not sure of his social class (and finds him a bit rude).
The gentleman asks the note-taker how he knows where everyone is from, and he answers that he studies phonetics. The flower-girl tells the man to mind his own business, and the man gets angry with her, telling her that someone who speaks with "such depressing and disgusting sounds has no right to be anywhere—no right to live."
The man is an educated academic, who studies phonetics. While he studies all sorts of accents and dialects, he shows a shockingly extreme prejudice against the flower girl's lower-class speech.
The note-taking man then says to the gentleman that the flower-girl's accent and dialect will keep her in the lower class, but that he could teach her to speak so well in three months that she would pass for a noble lady. He explains that this is his main job, teaching people to speak well.
Note that the man insists not that he could make the girl into a noble lady, but that he could teach her to pass as a noble lady. He both insists on the power of speech to affect how one is perceived, but at the same time thinks that the flower girl would always still be a flower girl besides this change in other people's perceptions of her.
The gentleman says that he himself is "a student of Indian dialects." He introduces himself as Colonel Pickering, and the note-taker introduces himself as Henry Higgins. The two are already familiar with each other's work in linguistics.
Pickering and Higgins' friendship is built upon their mutual admiration and respect for each other's academic work. Higgins never shows the same respect for Eliza because she is a woman.
Higgins and Pickering leave to get dinner together. Higgins reluctantly gives the flower-girl some money. Freddy finally returns with a cab, only to find that his mother and sister have left him to walk to a bus. The flower-girl takes the cab he has brought, leaving Freddy alone.
In a minor, humorous reversal of expectations, it is the lowly flower girl, not the well-off Freddy, who ends up taking the taxi. All of Freddy's chivalrous searching for the cab, meanwhile, gets him nothing but abandoned.