The play starts in London, in the summer evening. It’s raining cats and dogs, people run to the Covent Garden Market and to the cathedral of St. Paul to hide from the pouring water. Amongst the distressed is a refined elderly lady with a daughter. They both barely saved the evening dresses they are wearing from the rain and now are waiting for Fred, the son of a lady. Fred went to find a taxi and then return for them. Everyone except one man with a notebook are looking at the rain with hope. Fred appears in the distance, but he hasn’t found a taxi. He runs to the cathedral, where his mother and sister are waiting for him, but he is too desperate to reach the dry place to watch out and accidentally crashes into a dirty and untidy girl in rags who sells flowers on the street. The girl’s basket with violets falls to the ground and all the flowers are now in the puddles.
The girl starts shouting at him, cursing Fred so creatively and eloquently that poor young man sticks in place. A man with the notebook starts to write down something hastily (later we’ll learn he is a linguist and he is very interested in flower girl’s dialect and cursing talent at the moment). The girl starts to lament that all her flowers are now gone and begs the Colonel, standing nearby, to buy some flowers to save her from hunger. He gives her some money, just to get rid of the clingy girl, but doesn’t take flowers. Someone warns the girl that the man with the notebook is, probably, from the police and is now writing the complaint. She starts to cry. But the man suddenly comes to the girl and calms her down saying he is not a policeman. He also surprises everyone around by guessing the origins of each by their pronunciation.
Fred’s mother asks him to go look for a taxi once more. Soon, however, the rain stops and the lady with her daughter go to the bus stop. The Colonel approaches the man with the notebook saying that he is amazed by his skills. Both gentlemen introduce themselves: the man with the notebook is named Henry Higgins, the creator of the Universal Higgins Alphabet. The Colonel is a linguist too, he wrote and published a vast study about oral Sanskrit. His name is Pickering. He lived in India for a long time and the only reason for him to return to London is the possibility to see Professor Higgins. The Professor is very glad to see the Colonel because he read his book and was deeply impressed by it. But still, he thinks that his talent is superior, because he is not only a theoretician - he can turn the language of such a miserable creature as that flower girl to one of a Duchess in half of a year. The two men agree to go to the hotel Colonel stayed in and have a dinner and a conversation in a hotel restaurant, but the girl clings to them again, begging to buy more flowers. Higgins throws a handful of coins into her basket and leaves with the Colonel. The flower girl now sees that she has plenty of money comparing with her usual daily income. When Fred finally returns with the taxi, which is already unnecessary, the girl gets into the car and slams the door, returning home with comfort.
The next morning Higgins invites the Colonel to his home and laboratory on Wimpole street and shows him his phonographic equipment. Suddenly, Mrs. Pearce, his housekeeper, enters, saying that some young woman wants to see him and she doesn’t looks like his usual visitors. She said her name was Eliza Doolittle and she wanted to take phonetic lessons from the Professor, because her poor pronunciation doesn’t allow her to get a proper job. She said that the day before she heard from the Professor that he can give such lessons. Amused, Higgins lets her in. Eliza enters and repeats her offer. She is sure that yesterday Higgins was too generous and now will be glad to return the money he accidentally gave her. It sounds funny for both gentlemen - the coins were just change Higgins didn’t need - but Pickering reminds Higgins that Professor boasted yesterday that he could turn this flower girl into a proper lady with the language and manners of a Duchess in six months. Higgins offers the Colonel a deal. If Higgins succeeds, Pickering pays for the whole learning course for Eliza. Eliza herself, hearing that she can get the training for free, gladly agrees. Higgins orders Mrs. Pearce to take Eliza to the bathroom, wash her and dress her properly.
While Eliza is still in the bathroom, her father comes for her. He is a very simple man, but he really impresses Higgins with his natural eloquence - that’s who Eliza inherited her gift from. Eliza’s father is worried about his daughter, but Higgins convinces him that he doesn’t mean any harm or disgrace to Eliza. He also gives the man five pounds to completely calm him down. Meanwhile, Eliza, clean and brushed enters the room in a luxurious kimono. At first her father doesn’t even recognize her, to Higgins’ amusement.
Eliza starts her lessons. She tries as hard as she can, but Higgins treats her as a lab rat. After a couple of months, he asks his mother, Mrs. Higgins, to help him socialize Eliza. The old lady agrees and sends an invitation to one of her parties to Higgins himself and Eliza. It is her first serious exam. On the party there are the same people who saw Eliza as a flower girl: the mother, the daughter and Fred. However none of them recognizes the girl Higgins introduces as his relative. At first Eliza behaves perfectly ladylike - Higgins knows well all the traditional conversation topics and he trained the girl to answer every question she could be asked. But when the guests get really interested in the new beautiful and, seemingly, so educated girl, the conversation goes off the rails. Eliza herself relaxes a bit and her perfect English slips back to the street dialect when she starts to sincerely talk about her live. Higgins tries to save the situation pretending she is using some special words, so modern that they are yet unknown to the majority of people. Everyone believes (they are absolutely not used to street language, so it is easy to trick them). When the party is over, everyone is fascinated with such a wonderful young lady. Especially Fred, he falls in love with her from the first meeting and will send her ridiculously long romantic letters long after the party.
After the guest leave, Higgins and Pickering are very enthusiastic, discussing Eliza’s successes and failures right in front of her, like she is not a living woman but a race horse that has just won the race. Mrs. Higgins is disgusted and strictly lectures her son for treating a nice and kind girl in such a way. Mrs. Pierce, usually very reserved, agrees with her, saying that the men don’t think about the impact they may have on poor Eliza. But Higgins doesn’t really care. He indeed uses Eliza like a mix of a servant and a pet. He orders her to bring him shoes and totally ignores her outside of their lessons at home - but when they go out, to the opera, gallery or theatre, Higgins behaves like she is at least a Princess. Eliza becomes more and more depressed but he doesn’t want to think about it.
After a couple of months the final exam - the ambassador’s party - takes place. The introduction of Eliza is a great success, she is complimented and awed by everything like Cinderella on the royal ball. Eliza seems to be genuinely happy to be a star of the party… but then they return home and she turns into Cinderella again. Higgins and Pickering start to discuss their bet, not even bothering to congratulate her or treat her any better. We see the beautiful, tired and sad young woman dressed in an evening gown and incredibly expensive jewellery who is treated like a slave. When we notice that her depression and despair turn into wrath it is almost a relief.
Eliza steps forward, claiming that she and her hard work are also the part of Higgin’s success. She says that he completely broke her and made anew a different person Eliza doesn’t know yet. She has absolutely no idea what to do now and he just abandoned her like a used tool, not caring about her. Eliza isn’t a flower girl anymore. Neither she is a real Duchess. Higgins annoyingly replies that she may consider marrying someone. Enraged, Eliza starts to scold him brilliantly and eloquently, showing Higgins his own selfishness, until he loses her temper and nearly hits her. With a cruel and delighted smile, Eliza throws the slippers she was ordered to bring into Higgins’ face, returns him the jewellery and goes to her room. Higgins, shocked and offended, shouts that she is ungrateful and spoiled. For him it looks like his furniture calls him out for slamming the cabinet’s door too hard.
The next day Higgins, in anger and panic, rushes to Mrs. Higgins, saying that Eliza has run away (right, the mother is the most appropriate person to deal with girl leaving you…). Higgins and Pickering search everywhere, but Eliza is nowhere to be found. They even want to call the police, but Pickering figures out that Eliza isn’t their relative and - legally - isn’t their missed property as they thought before. Moreover, when Eliza leaves, Higgins is left utterly helpless: he is so used to use her as a free servant and secretary that now he doesn’t know where his things are, what are his appointments for today and lacks lots of other things that, as he thought, happened just naturally.
In addition, Eliza’s father comes to Higgins, complaining that he ruined his life. It appears that Higgins wrote a letter to one American millionaire for his amusement, recommending Mr. Doolittle as one of the most original modern self-educated philosophers and moralists despite him being a simple scavenger. The millionaire appeared to be the founder of the League for moral reform, so he was amazed to hear about such a virtuous man. But soon everything went wrong. The millionaire suddenly died and bequeathed a decent part of his money - three thousand pounds of annual income - to Doolittle to support his talent. It seems the scavenger, now well-dressed, cleanly shaved and looking like a gentleman, should be happy, but he is as shocked and lost as his daughter was yesterday. He almost repeats Eliza’s words: he doesn’t know what to do now and how to behave. He can’t be a scavenger anymore, but he has yet to find his new role to fit the society. Moreover, according to the last will of the millionaire, Doolittle now has to prepare up to six lectures a year in the League of moral reforms. Doolittle laments that now he even has to bother about wedding the woman he lived with for so many years - Eliza’s mother - because he shall be the example of moral and socially acceptable behaviour.
Mrs. Higgins sincerely congratulates Mr. Doolittle, hoping that now, with his new income, he will be able to take care about his reformed daughter and together they will manage to establish their new life. But Higgins himself refuses to “return” Eliza to her father. As awful as it sounds, he still considers that he “bought” her and the girl is his property. The thing is that he has to find her somehow.
Mrs. Higgins steps in and says that she knows where Eliza is. But she also knows that Eliza won’t return until Higgins sincerely apologizes. Higgins is angered with a mere thought of apologizing before a flower girl. Then Eliza comes downstairs - it appears that Mrs. Higgins was hiding her in her room all along. She now looks even more beautiful than yesterday and she heard every single word Higgins said. Eliza thanks to Pickering (who indeed was better to her) for treating her as a person and as a lady, comparing him to rude and ignorant Higgins. Then she turns to the linguist and says that if he ever treats her in such a way again or says a single foul word to her, she will immediately go to Professor Nepommuck, Higgins’ rival, become his assistant and give him all the information about her lessons and everything else she learned about Higgins’ studies.
When Higgins is able to overcome the initial shock he has to admit that now Eliza has not only the language and manners of a Duchess, but also the dignity. He adds that now he respects her and admires, unlike the flower girl who kept his house and brought him slippers. He is sure that they can live together not like just two smart men and one stupid girl but as “three old bachelor friends”.
Eliza leaves this offer unanswered, leaving to attend her father’s wedding. Despite she is still out of place in the society, she now has a rich family, a respected father and an aristocratic suitor. But most important - Eliza indeed finds her dignity, confidence and self-esteem, so we can hope that her future life will be happy.