Amelia and Becky are both students at Miss Pinkerton’s school for girls. Becky is an orphan who is clever but rebellious, while Amelia comes from a relatively well-off family and is typically meek and obedient. When they graduate, they each receive a dictionary, but Becky quickly throws hers out the window of a carriage.
Becky has been hired as a governess, but before that, she spends some time with Amelia’s family, where she attempts to get a marriage proposal out of Jos, Amelia’s brother, who is wealthy from his business dealings in India. During her visit, Becky also meets George, whom Amelia has planned to marry since they were both children. George’s best friend is Dobbin, who secretly loves Amelia but is loyal to George and believes the best way to make Amelia happy is to help with her marriage to George.
Ultimately, Becky fails to marry Jos, so she goes on to her governess job with the family of Sir Pitt. Sir Pitt likes Becky right away—so much that when Lady Crawley dies, he proposes to Becky. Becky has to turn him down, however, because while she was working as a governess, she secretly married Sir Pitt’s son, a boisterous army captain named Rawdon.
When the famous historical figure Napoleon escapes his exile and begins waging war again in Europe, Amelia’s father, Mr. Sedley, suddenly goes bankrupt, forcing the whole family to move into a smaller house. At the Sedley estate sale, Dobbin sees a piano that he knows Amelia loved, so he buys it and sends it back to her (although she believes George sent it). The bankruptcy also causes George’s father, Mr. Osborne, to forbid George from marrying Amelia. George himself likes his reputation as a ladies’ man and seems happy at first about getting out of his engagement to Amelia. But Dobbin, wanting the best for both George and Amelia, convinces George to go through with the marriage. George does so, causing his father to disinherit him.
As Napoleon approaches Belgium, Rawdon, George, and Dobbin all must go to fight, with Rawdon and George taking their new wives with them. Although the British defeat Napoleon at Waterloo, George dies in combat, leaving Amelia a pregnant widow. When Amelia eventually gives birth, she names her son George (Georgy) in honor of his dead father. Amelia continues to obsess over George even after his death, keeping his portrait up on the wall. Despite Dobbin’s love for Amelia, she isn’t able to move on after George’s death.
Meanwhile, Becky and Rawdon give birth to a son they call Rawdy, and they manage to live a relatively wealthy lifestyle without having any official source of income. This is partly because Rawdon manages to win money by hustling people at billiards and partly because Becky attracts the attention of the wealthy Lord Steyne, who seems to want to have an affair with Becky but maintains a respectable appearance when they’re in public.
One day, Rawdon gets sent to debtor’s prison (since he and Becky both owe many debts due to their extravagant lifestyle). When he gets out, he comes back to find Lord Steyne and Becky in a room alone together. Rawdon angrily implies that it looks like Becky was cheating on him. He storms off, intending to challenge Lord Steyne to a duel, but Lord Steyne instead arranges for Rawdon to get a paid appointment to act as governor of a remote island. Rawdon accepts the position and goes off to the island, where he eventually dies of yellow fever.
Meanwhile, Amelia continues to be an attentive mother to Georgy, but her whole family is in a dire financial situation, with Mr. Sedley continuing to make bad decisions with money. One day, Mr. Osborne meets his grandson Georgy and proposes that he could raise Georgy and pay Amelia some money for Georgy’s custody. While Amelia is initially offended, ultimately, she feels like she has no choice but to go along with it and let Georgy go. Under Mr. Osborne, Georgy quickly learns how to be a gentleman, giving commands to everyone and drinking too much alcohol for his young age. Eventually, however, with some help from Dobbin, Mr. Osborne reconciles with Amelia; when he dies, he leaves her some money and Georgy.
Eventually, Amelia, Jos, Georgy, and Dobbin all go to Pumpernickel in Germany on a vacation. There, Jos and Georgy happen to run into Becky at a gambling hall. It turns out that all of Becky’s former friends like Lord Steyne have abandoned her, and now she wanders across Europe, struggling to make money. Jos invites her to come with them, and over time, Becky manages to win Jos over again. Meanwhile, Dobbin finally confesses his love to Amelia, but she still isn’t ready to let go of George. Dobbin leaves to go back to India with his regiment.
Becky, however, still feels that Amelia should marry Dobbin. She shows Amelia a note that she’s kept hidden for a long time: in it, George writes that he wants to run away with Becky and abandon Amelia. Finally able to let go of George now that she can see his flaws, Amelia writes to Dobbin immediately, asking him to come back. Dobbin returns, and he and Amelia soon marry and have a child together. Meanwhile, Becky succeeds in exercising her control over Jos, managing to drain all the money out of his various accounts. Jos becomes feeble and dies, possibly due to foul play by Becky (who receives a portion of his life insurance), although this is never confirmed. Becky uses her new money to get involved in charity and a local church, although when the others see her, they continue to be suspicious about whether Becky has truly changed.
