The novel’s postscript is a copy of a speech Dickens gave upon his second visit to the United States, over 20 years after the novel’s publication. He specifically requested to include this speech in all forthcoming editions of the novel, as he details how much the United States has changed for the better since his last visit, particularly regarding its abolition of enslavement.

The Chuzzlewit family is introduced as one of the oldest in England, and quite respectable. The narrator details the family’s likely connections to the Gunpowder Plot and other episodes of English history. Though they don’t have land or title, the Chuzzlewits are wealthy and prideful, with a few bad eggs in the family.

In a village in Wiltshire in Autumn, a strong wind blows into the home of the Pecksniffs, knocking over Mr. Seth Pecksniff and frightening his daughters, Mercy and Charity. The narrator discusses the amiable qualities of the daughters, nicknamed Merry and Cherry, and the father’s reputation as a man of superior morals. However, Pecksniff’s reputation is unfounded, as he makes a living by tricking young men into paying tuition to learn his profession of architecture, while using his students’ designs as his own to make a profit. He often hypocritically soliloquizes on morality and tries to instill the same attitude in his daughters.

Pecksniff tells his daughters about a young new apprentice whom he will be teaching, and they discuss the other apprentices, John Westlock and Tom Pinch. The men suddenly arrive at the Pecksniffs’ home, with John wanting to make up with Pecksniff for their differences before he leaves his tutelage. Pecksniff won’t apologize to the man, who recounts the ways Pecksniff has financially taken advantage of him over the years. John tries to convey to Tom how cruel Pecksniff is, but Tom is loyal to the architect and only wants his friend to reconcile with their boss.

Once they leave, Tom defends Pecksniff to John, and John commends his good nature while taking pity on his naivety. John gets into a carriage headed for London, where he is moving.

The next day, at a neighborhood inn called the Blue Dragon, a sick old man and a young lady arrive and take a room. Though the man dismisses anyone’s offers of help, the inn’s landlady tries to summon learned men of the village before he falls asleep.

That night, the landlady, Mrs. Lupin, and the old man’s companion, Mary Graham, speak to one another as the man sleeps. They discuss how Mary is not related to the old man, stunning Mrs. Lupin for what she regards as the impropriety of the arrangement. It is later revealed that the man is Old Martin Chuzzlewit, the rich yet deeply suspicious patriarch of the Chuzzlewits, who is afraid his family is scheming to get his money. Mary is employed as his companion and nursemaid. Mary is only paid for her work for him and is not included in his will, so he can trust her more than his family members. Old Martin is afraid that even Mrs. Lupin is scheming with a family member, in spite of meeting her only that day.

As Mrs. Lupin leaves Old Martin’s room, she runs into Pecksniff, whom she had called to help look after the sick man. She discusses her suspicions with Pecksniff, who enters the room to see Mary. Old Martin wakes a few moments later, and Pecksniff is surprised to recognize the man as his cousin. Old Martin is suspicious of Pecksniff, even having dreamed of him scheming to get his money just moments before. Pecksniff tries to assuage his worries by noting the coincidences that brought them together.

Old Martin tells Pecksniff that having money has ruined his life, yet he can’t get rid of it to ruin the lives of others. He tells Pecksniff how Mary was an orphan he adopted, explaining their financial ties and how she is his only true friend. As respectfully as possible, Pecksniff tells Old Martin his hoarding is wrong, especially since he has a grandson to take care of, who should be financially provided for. Pecksniff leaves, and Old Martin debates whether or not Pecksniff is right.

In the following days, Pecksniff hovers around the Blue Dragon to eavesdrop on Old Martin. There, he runs into Chevy Slyme, another Chuzzlewit cousin, and his scheming friend, Montague Tigg. These men want to speak with Old Martin, believing they have some right to part of his fortune, but also let Pecksniff know that other relatives—such as Mrs. and Mr. Spottletoe and Anthony and Jonas Chuzzlewit—plan to do the same. Tigg, speaking for Slyme, proposes forming a union against Old Martin to get him to give up his money, horrifying the outwardly moral Pecksniff.

By the end of the day, the village’s taverns are full of Chuzzlewits from all branches of the family, yet Old Martin refuses to see any of them. Many of the feuding relatives gather at Pecksniff’s house to discuss how they will persuade Old Martin, with Pecksniff as the arbitrator. Various named and unnamed Chuzzlewits quarrel over old family grudges, but they all agree that Old Martin’s relationship with Mary is improper, as they believe she has designs on his fortune.

However, as they try to form a plan, news arrives that Old Martin and Mary have left, and many believe that Pecksniff had gathered them all at his house to keep the Chuzzlewits away from their patriarch.

Pecksniff sends Tom Pinch into town to fetch Pecksniff’s new pupil, and many people along the road come to say hello to their friend Tom. He runs into his friend Mark Tapley, a cheerful employee of the Blue Dragon, also going into town, and offers him a ride in Pecksniff’s carriage. Mark reveals that he plans to leave the Blue Dragon, despite courting Mrs. Lupin, because he believes his job is not gloomy enough to do his good humor any credit, astonishing Tom. Once the strange man leaves the carriage for Salisbury, Tom takes delight in the pleasures of the bustling town, especially its bookshops and cathedral.

Tom eventually meets the pupil he was waiting for, a charming young man whom he is surprised to learn is Martin Chuzzlewit, the grandson of the rich old man of the same name who was recently in town. The two men get along well. Tom tells Martin the virtues of Pecksniff and how he plays the organ for the village church, where he recently saw a beautiful young woman watching him play.

They arrive at the Pecksniffs’ home early, surprising the family, but Pecksniff embraces Martin as family while the daughters try to flirt with him. They all dine together, but before bed, Pecksniff warns Martin that Tom is unpolished and can sometimes forget his station.

At breakfast the next morning, Tom notices how Pecksniff treats Martin differently, and how Martin himself acts more freely than Tom would ever dream of doing. The family is unusually happy because they are soon going to London on Pecksniff’s business, and he leaves Martin in charge of the house. Pecksniff summons Martin for a private conversation, which Tom sees leaves Martin less cheerful all day. Tom reflects on how well Pecksniff treats him in a letter to his sister, Ruth, as Pecksniff overworks him in getting his things ready for London.

Later that night, Martin confides in Tom his troubles, telling him how he grew up expecting to be wealthy, but was recently disinherited by his selfish grandfather. Martin fell in love with Mary, who also loved him, but when Old Martin found out about how his grandson planned to upset his plans for Mary, he sent away his grandson, believing he too was scheming to get his fortune through Mary. Martin saw Pecksniff’s advertisement once he left his grandfather’s house, and became interested in the apprenticeship because he knew Old Martin didn’t like Pecksniff.

Martin also tells Tom that the beautiful young woman who came to listen to his organ-playing must have been Mary, and Tom gives up all hope for the crush out of deference to Martin. Ever the optimist, Tom tries to reassure Martin that everything will go well, yet Martin continues to treat him as one beneath his station.

Tom and Martin’s friendship grows as he works on the architectural designs Pecksniff assigned them, though Martin continues to patronize Tom. Tigg finds them one day, and requests from Tom a letter Pecksniff left for Chevy Slyme, including some money, but Tom knows nothing of the letter or the money.

Tigg ultimately reveals that he and Slyme have been detained at the Blue Dragon because neither has any money to pay their bill, and Mark Tapley followed Tigg to the house to make sure he doesn’t escape without paying. Martin pulls Tom aside to tell him that he hasn’t heard good things about his cousin Slyme and would like him out of town. They make a plan to assure Mrs. Lupin, a friend of Tom’s, that she will be paid, so Slyme and Tigg can be released.

They all go back to the Blue Dragon, where they run into Slyme, who is drunk and sulking after being obliged to strangers for his tavern bill. Once Slyme passes out, Tom lends Tigg his last money for traveling, on Tigg’s stipulation that he will give it back to him by the end of the week. Tom learns that Mark plans to leave the Blue Dragon for London, where he hopes to find a bad job to test the mettle of his cheerfulness, further confusing Tom. Before he leaves, Mark confesses his feelings for the widowed Mrs. Lupin, but she thinks his proposals of marriage are nonsensical, so they agree to remain friends.

Pecksniff and his two daughters take the postal carriage to London and run into Anthony Chuzzlewit and his son Jonas along the way. Jonas flirts with both Merry and Cherry as their fathers sleep in the carriage.

They separate upon arriving in London. The Pecksniffs go to a dark boarding house run by Mrs. Todgers, an old friend of Pecksniff’s. Though Mrs. Todgers only takes men in her boarding house, Pecksniff asks her to keep his daughters in her own room, which she does.

Todgers’s boarding house is located in a maze of alleyways in a dingy and crowded part of London, and its owner quickly befriends the two Pecksniff daughters. They all plan on going into town to see Ruth Pinch, Tom’s sister and a governess for a wealthy family, whom Merry and Cherry have always wondered about. The ladies are surprised to learn that Ruth isn’t ugly and unrefined, like her brother. Pecksniff gives Ruth a letter from Tom. Ruth thanks Pecksniff for taking care of her brother, and the party leaves, but not without being harassed by the owner of the mansion as they go. Ruth is scolded for the Pecksniffs’ intrusion, but Pecksniff is somewhat offended at being treated so poorly.

Bailey, a boy who works for Mrs. Todgers, teases the Pecksniff daughters rather than helping to prepare dinner, where the boarders at Todgers’s all dine together. They meet characters like Mr. Jinkins, Mr. Gander, and other long-term boarders who all flirt with Merry and Cherry. The company all drinks heavily. Pecksniff comes to Mrs. Todgers, lamenting about his daughters growing up and his late wife, whom Mrs. Todgers reminds him of. After nearly confessing his tuition scheme to Mrs. Todgers, Pecksniff drunkenly falls into the fireplace, but isn’t burned. The other boarders help him to his bed, but Pecksniff repeatedly gets out to moralize to his company.

For days, Pecksniff waits for a letter at the post office. The day after one from Old Martin arrives, the man comes to Todgers’s. It is revealed that Pecksniff’s business in town is to speak with Old Martin, whose thoughts about Pecksniff have changed. Old Martin now trusts Pecksniff and wants him as a friend and ally, along with his daughters.

Old Martin knows about his family’s meeting behind his back at Pecksniff’s house, and knows that his grandson is apprenticing with him. Old Martin tells Pecksniff that his grandson is engaged without Old Martin’s approval, and urges Pecksniff to turn the younger Martin out of his house. Pecksniff is shocked and tells Old Martin to consider it done, also agreeing to treat Mary like one of the family at Old Martin’s request. Old Martin asks Pecksniff to keep his secrets, knowing that all the other Chuzzlewits will think Pecksniff is scheming to get his fortune.

Once the old man leaves, the Pecksniffs overhear a young boarder named Augustus Moddle arguing with Mrs. Todgers about Mr. Jinkins in the next room, threatening to leave because he feels excluded by the other man, who had been keeping him from flirting with Merry the previous night.

Jonas comes to call upon Cherry after meeting Pecksniff in the street, and tells her about how he hates his father, because he thinks he has lived too long and kept Jonas from his inheritance. Pecksniff has agreed to let Jonas take Cherry and Merry to see his father, despite neither woman wanting to go, and they all dine together uncomfortably. They are joined by Mr. Chuffey, Anthony’s clerk and old friend, who engages very little with anyone but Anthony. As Jonas makes fun of Chuffey, Anthony takes pride in how he has raised his son to be so callous and selfish.

Jonas keeps the ladies at dinner late and walks them home, flirting with Cherry but keeping his eye on Merry all night. The night before they leave London, the boarders of the house serenade the ladies with laments, and Bailey follows them around as they pack. Anthony and Jonas are announced at Todgers’s as the Pecksniffs are leaving, where the fathers discuss a possible relationship between Jonas and Cherry, surprising and confusing Pecksniff.