The story starts from the graduation of the two classmates - the polar opposites of each other. One girl is named Becky Sharp and she is from the dysfunctional family of a former art teacher who abuses alcohol. Amelia Sedley is the descendant of the middle-to-upper class family of a property investor. They have absolutely different worldview: Becky, who didn’t have a proper childhood, learned to be mature and rely on herself only, while Amelia is still a naive child who is sure that her family will protect her everywhere.
Becky finds a job of a governess, but her friend invites her to spend some days in her family home before Becky goes to the job. However, Becky is practical as always: she learns that Amelia’s older brother has a well-established position in India, she decides to seduce him and marry. But the plain fails because of the personality of Jos Sedley: nerdy, shy towards girls but very self-righteous and vain. Becky tries her best to make him interested in her, but her flirting is for nothing: Jos gladly accepts her affection giving nothing in return. Finally, they gather a big company to go to Vauxhall, the local concert hall. Amelia, Becky and Jos go together with Amelia’s suitor George Osborne, as vain and proud as Jos, just more handsome, and William Dobbin, an idealistic army officer and George’s friend. George despises Becky from the first glance and, not wanting a sister-in-law of low origin, starts to taunt Jos for his affection. Jos is ashamed of Becky and her plan is completely ruined.
Her time with the Sedleys comes to an end and Becky moves to the house she is going to work: the Queen’s Crawley estate. The estate belongs to Sir Pitt Crawley, an old nobleman with the temper as nasty as Jos’ and George’s put together. The duty of Becky is to teach his two children, but gradually she becomes the informal manager of the whole estate and the personal secretary of Pitt Crawley. Being already vitally important for him as manager, she doesn’t put too much pressure on her students and they love her for that. Oldest son Pitt Jr. is prissy and nerdy and she pretends to be the same with him, allowing some innocent flirt with the younger son, Rawdon, who is fond of army and manly manliness.
The rest of the Crawley family includes Sir Pitt’s younger brother Bute with his wife (who dislikes Becky from the first sight) and his half-sister, Miss Matilda Crawley, a fat and generally unpleasant old lady who is very rich though. She loves Rawdon and there are rumors in the family that he is going to inherit all her fortune. Everyone in the house pretends that they love her, but Miss Crawley finds Becky adorable and demands her for herself in London. Becky moves there and becomes her maid, caring for the old lady during her illnesses. Sir Pitt, whose management skills are much worse than Becky’s, can stand her absence only for a few months, then he comes and asks her to return. Becky doesn’t want to: she got used to the life in the capital. But then Sir Pitt blatantly makes a proposal to the shocked maid. Becky hesitates but then reveals that she is already married. This night she runs away from the house of Miss Crawley, leaving a note saying that she is married to Rawdon. Enraged, Miss Crawley disowns Rawdon and changes her will to not let him get anything.
In the meantime, Amelia’s family experiences some financial troubles. The business of her father isn’t going well, and Napoleon is planning another war. This fact turns over all the stock markets, so Mr. Sedley is left with almost nothing. Seeing the misfortunes of the Sedleys, Mr. Osborne, the father of her fiancee George demands his son to break the engagement. George refuses, but only because it would ruin his reputation. The things in Sedley family go even worse up to the bankruptcy. All their property is sold on the auction and they have to settle down in a cramped house on the outskirts. Mr. Sedley, who considered Mr. Osborne his friend, is enraged that Mr. Osborne now just ignores him and orders his daughter to break the engagement too. Amelia obeys, but her tender nature can’t stand this act and she falls ill because of a broken heart. Mr. Osborne threatens to stop giving George money if he will still be interested in Amelia and insists in his marriage with a rich girl. George proudly refuses, but when Amelia breaks the engagement first, he feels that his reputation is saved and just ignores her completely from that moment on.
Dobbin, though, does care. When he visits Amelia once and sees her state, he rushes to George and says she is dying of love. Horrified, George immediately returns to her and makes a proposal without telling his father about this decision. Amelia gradually recovers and she, George and Jos decide to spend their honeymoon in Brighton. Coincidentally, Becky and Rawdon are also having a vacation there. Becky chose this place, because she knows that Miss Crawly is also here and hopes that she will see how happy they are and forgive them. Dobbin decides to stay in London and finally tells Mr. Osborne about George’s marriage. George though feels bored as a married man, spending more time with Rawdon playing cards than with his wife.
Miss Crawley, without her maid, is left for care of the wife of Bute Crawley, who has the ugliest temper and is a little house tyrant. Miss Crawley understands that Becky isn’t the worse option and starts communicating with her. In the meanwhile, Mr. Osborne claims that he has no son anymore.
The war starts, and everyone connected to army - George, Dobbin and Rawdon - have to move to the gathering point in Belgium. Becky and Amelia go with their husbands and Jos follows them without any reason. George and Dobbin are again at the same regiment, while the wife of the commander takes care of Amelia. Soon Becky and Rawdon (who serves as aide-de-camp to one of the generals) arrive too and Becky immediately draws all the attention towards her. George is completely fascinated with her too, forgetting about Amelia completely. Once he passes Becky a note, asking her to run away with him. But this very night the army gets an emergency order to immediately march to the frontline. Before leaving, George apologizes to Amelia and seems to make up again with her. Becky says her farewell to Rawdon, already calculating her pension for his death.
For some time there is no news about the army. The panic starts to rise, and people start to flee. One of the first cowards is Jos. He searches for the horses, but no one wants to sell them, thinking that they might be useful for their own escape. Becky has two horses and sells both to Jos, making a lot of money at once. When Jos departs the news finally reach Brussels: the battle at Waterloo is won. Dobbin and Rawdon are unscratched, but George is dead.
Becky goes to Paris with her husband. She gets pregnant and they have a son she neglects almost completely. Rawdon, on the contrary, becomes a caring father who loves his son above all else. In the meanwhile his brother Pitt Jr. marries the shy and sweet Lady Jane and they have two kids. Miss Crawley finally finds a sweet girl who cares for her and rewrites her will again to leave everything to Pitt and Lady Jane. Sir Pitt dies soon thereafter, leaving everything to Pitt Jr. too. Rawdon is enraged with this decision, but Becky acts cleverer and behaves as a gracious loser, making friends with Pitt and Lady Jane instead.
Amelia doesn’t take George’s death well. It gets worse when she realizes she is pregnant and has no income to raise the baby. Jos and the commander’s wife take care about her for a while, but then Amelia has to return to the house of her parents. There she gives birth to a boy and loves him more than her life. She may not buy herself food, but her son shall always have the best clothes, toys and books. Dobbin becomes the godfather of the boy and helps a lot, while Mr. Osborne still refuses to acknowledge his grandson.
Becky and Rawdon return to England and visit Pitt and Lady Jane. Becky is charming and quickly wins their heart, she is even hired to manage the restoration of his London mansion. But the things go wrong, when her son unwillingly reveals her true nature, accidentally saying that Mom never spends time with him at home as much as here. Lady Jane immediately understands that something is wrong, but Pitt still considers Becky a nice person, so she departs to London to start her job. There Becky is noticed by Lord Stayne, a very, very powerful, old, immoral and depraved aristocrat who is the adviser of the King. Lord Stayne introduces her to the high society, hoping to get her affection in exchange. Becky understands everything and friendzones Lord Stayne as much as possible, while her husband spends time in idleness and gambling with other admirers of Becky (whom she deliberately invites, knowing that her husband can win them some money). Lord Steyne’s wife is forced to befriend Becky and later the young woman is introduced to the King himself.
The Sedleys aren’t doing well at all. Jos sent them some money for a while and Amelia received a pension from George’s death in battle. But the real troubles arise when Mr. Sedley starts to speculate on stock market and loses again, up to the point they don’t have money to buy food. Amelia still naively believes that her father will sort the things out, still buying her son the best things. She is saved in an unexpected way. The sister of deceased George pays them a visit and sees how much Amelia’s son resembles her brother. She tells Mr. Osborne about what he seen and after some heavy thoughts he offers Amelia to actually sell her son to him for the steady monthly allowance and permission to see him from time to time. Amelia, naturally, freaks out and refuses, but when the financial state of the family drops to the absolute zero, she understands that she has no choice. Mr. Osborne pampers his grandson and raises him almost a copy of George - arrogant, handsome and self-righteous, but still, Amelia’s influence leaves something kind and caring in him. Amelia’s parents die and soon Mr. Osborne dies too, leaving a huge fortune to his grandson and still mentioning Amelia’s allowance in his will.
Becky is now a star in the high society. She throws a huge masquerade party, dressing up as Clytemnestra, the mythology character: the Greek queen who killed her husband. Lord Steyne understands the hint while others are just admiring her. Late at night Rawdon takes her home and decides to have a walk himself. During this walk he is suddenly arrested and put into debtor’s prison. He immediately writes to his wife, asking to bring him money to pay the debt but gets no response. The next day he gets the answer that Becky was too busy yesterday, today she feels ill and will bring him money only tomorrow. Enraged, Rawdon writes to Lady Jane, who immediately brings him the sum needed. Rawdon returns home just to see his wife with Lord Steyne in the dining room involved into a very frivolous situation: Becky in her best dress is singing songs to him, sitting too close to Lord Steyne. Furious, Rawdon punches Lord Steyne, tears apart Becky’s dress and storms off the house. Later, coming to his senses, Rawdon understands that punching someone of Steyne’s status won’t do him any good. But later he receives a letter from Steyne’s lawyer, who assures Rawdon that Lord Steyne understands everything and even offers Rawdon the appointment of governor of one of the islands somewhere far away at the border of British Empire. Rawdon leaves London, going to the island alone and giving his son to Pitt and Lady Jane. He still pays Becky allowance as an honest man.
Becky travels across Europe but the same story continues to happen. She charms everyone, enters the high society and then some very convenient and well-timed rumors get her exiled from it. She understands that Lord Stayne hasn’t forgiven her either, making sure that she will have as many troubles with the aristocracy as possible.
After the death of Mr. Osborne Amelia is finally free to raise her son. She with the kid, Dobbin and Jos goes to travel across the Europe. In Germany Jos accidentally meets Becky, poor and broken, living in aa decrepit hut she decorated as tastefully as she could. Dobbin warns everyone that being with Becky won’t do them any good, but Jos still takes her with them. Dobbin finally finds the courage to confess to Amelia, but she still feels guilty because of George’s death and decides to stay faithful to the deceased husband. Embittered, Dobbin says that he is leaving, because the years of unrequited feelings torment him. Amelia feels broken after Dobbin’s departure but can’t move on still. Seeing her struggles, Becky pities her and shows her the note George once gave to her, asking Becky to elope with him. This note liberates Amelia. Not feeling obliged anymore, she writes to Dobbin saying that she accepts his proposal. The couple return to London and Amelia gives birth to a daughter. Dobbin gradually realizes that his ideal dream Amelia is different from the real-life Amelia, but despite this he is still nice to her for the rest of their days.
After the death of Rawdon and Sir Pitt, Becky’s son inherits everything. He befriends Amelia’s son but never tries to reconcile with his mother. Becky marries Jos and they travel the world, until Jos mysteriously dies. Becky demands his life insurance policy as his widow, hiring the best lawyers to get it (though everyone suspects that it was a poisoning and Becky is a murderer). Becky wins the trial and gets a lot of money, spending the rest of her life in Bath, living a modest but happy life with her loyal friends, lots of fun and charity to do.