Selfishness is a strong family trait in Martin and Anthony Chuzzlewit, two aged brothers. From his cradle, Anthony’s son, Jonas, has been taught to think only of money and gain; in his eagerness to possess his father’s wealth, he often grows impatient for the old man to die. Old Martin Chuzzlewit suspects the world of having designs on his fortune; his distrust and lack of generosity have turned his grandson, his namesake, into a model of selfishness and obstinacy. The old man’s heart is not as hard as it seems, for he has taken into his house as his companion and ward an orphan named Mary Graham. He tells her that she will have a comfortable home as long as he lives but that she should expect nothing at his death. His secret wish is that love might grow between her and his grandson, but when young Martin tells him that he has chosen Mary for his own, old Martin is displeased, afraid that the young couple are acting in their own interests. A disagreement follows, and the old man turns his grandson out of his house.

Thrown on his own resources, young Martin decides to become an architect. He arranges to study with Mr. Pecksniff, an architect and land surveyor, who lives in a little Wiltshire village not far from Salisbury. Mr. Pecksniff agrees to train two or three pupils in return for a large premium and exorbitant charges for board and lodging. He thinks highly of himself as a moral man, and he has a copybook maxim to quote for every occasion. He and old Martin Chuzzlewit are cousins, but even though there has been bad feeling between them in the past, Mr. Pecksniff sees in young Martin a possible suitor for one of his daughters, and he accepts him as a student without requiring the customary fee.

Mr. Pecksniff has never been known to build anything, a fact that takes nothing away from his reputation. With him live his two affected daughters, Charity and Mercy, both as hypocritical and mean-spirited as their father. His assistant is a former pupil named Tom Pinch, a meek, prematurely aged draftsman who looks upon Mr. Pecksniff as a tower of knowledge.

Young Martin arrives in Wiltshire and takes the place of John Westlock in Mr. Pecksniff’s establishment. Westlock was never a favorite in the household, his contempt for Mr. Pecksniff having been as great as his regard for the honest, loyal Tom Pinch. At first, Martin treats Tom in a patronizing manner. Tom, accustomed to the snubs and ridicule of Charity and Mercy, returns Martin’s slights with simple goodwill; before long, the two become friends.

One day, Mr. Pecksniff and his daughters depart suddenly for London, summoned there by old Martin Chuzzlewit. The old man calls on them at Mrs. Todgers’s shabbily genteel rooming house and accuses his grandson of having deceived the worthy man who shelters him. Mr. Pecksniff pretends to be pained and shocked to learn that Mr. Chuzzlewit has disowned his grandson. When the visitor hints at future goodwill and expectations if the architect will send the young man away at once, Mr. Pecksniff—even though the old man’s proposal is treacherous and his language insulting—agrees eagerly. Returning to Wiltshire, he puts on a virtuous appearance as he announces that young Martin has ill treated the best and noblest of men and has taken advantage of his own unsuspecting nature. His humble roof, Mr. Pecksniff declares, can never shelter so base an ingrate and impostor.

Homeless once more, Martin makes his way to London in the hope of finding employment. As the weeks pass, his small store of money dwindles steadily. At last, when he has nothing left to pawn, he decides to try his fortunes in America. A twenty-pound note in a letter from an unknown sender gives him the wherewithal for his passage. Mark Tapley, the hostler of the Blue Dragon Inn in Wiltshire, accompanies him on his adventure. Mark is a jolly fellow with a desire to see the world. Martin cannot leave London, however, without seeing Mary Graham. He reads her a letter he has written to Tom Pinch, in which he asks his friend to show her kindness if the two should ever meet. Martin also arranges to write to Mary in care of Tom.

As steerage passengers, Martin and Mark have a miserable voyage to New York. Martin is not fond of the bumptious, tobacco-chewing Americans he meets, but he is excited by accounts of the fortunes to be made out West. Taken in by a group of land promoters, he writes to Mary, telling her of his bright prospects.

Meanwhile, old Anthony Chuzzlewit dies suddenly in the presence of his son, Mr. Pecksniff, and a faithful clerk, Chuffey. Sarah Gamp is called in to prepare the body for burial. She is a fat, middle-aged Cockney with a fondness for the bottle and a habit of quoting endlessly from the sayings of Mrs. Harris, a friend whom none of her acquaintances has ever seen.

After the burial, Jonas Chuzzlewit goes with Mr. Pecksniff to Wiltshire, for his cautious inquiries have revealed that Mr. Pecksniff is prepared to make a handsome settlement on his daughters, and Jonas is ready to court one or the other. A short time later, old Martin Chuzzlewit and Mary Graham arrive to take rooms at the Blue Dragon Inn in the village. There Tom Pinch meets Mary and, in his humble manner, falls deeply in love with her. Only his friendship with Martin keeps him from declaring his love to her.

Mr. Pecksniff had hoped that Jonas would marry Charity, his elder daughter, but Mercy is the suitor’s choice, much to her sister’s chagrin. After the wedding ceremony, Mr. and Mrs. Jonas Chuzzlewit return to London, and before long Jonas begins to treat his bride with ill humor and brutality. Having some business to transact at the office of the Anglo-Bengalee Disinterested Loan and Life Insurance Company, Jonas discovers that Mr. Montague, the president, is in reality Montague Tigg, a flashy speculator whom Jonas had previously known as an associate of his rascally cousin Chevy Slyme. Lured by the promise of huge profits, Jonas is persuaded to invest in the company and become a director. Tigg, however, has little trust for his new partner, and he tells Nadgett, his investigator, to learn whatever he can about Jonas.

Jonas has a guilty secret. Before his father’s death, he obtained poison from a debt-ridden young doctor and mixed it with old Anthony’s medicine. Actually, his father did not take the dose, but the circumstances, of which Chuffey, the clerk, is also aware, would be incriminating if they were to become known. Nadgett uncovers this secret, and the information gives Tigg a hold over his partner.

In Wiltshire, old Martin Chuzzlewit’s condition appears to be deteriorating. When his mind seems to fail, Mr. Pecksniff sees an opportunity to get control of his kinsman’s fortune. He hopes to make his position doubly secure by marrying Mary Graham, but Mary finds his wooing distasteful. When she tells Tom Pinch about his employer’s unwelcome attentions, Tom, for the first time, realizes that Mr. Pecksniff is a hypocrite and a villain. Having overheard the conversation between Mary and Tom, Mr. Pecksniff discharges Tom after telling Mr. Chuzzlewit that the young man has made advances to Mary. Tom then goes to London to see his sister Ruth. Finding her unhappily employed as a governess, he takes her with him to hired lodgings and asks John Westlock, his old friend, to help him in finding work. Before Westlock can provide him any assistance, however, an unknown patron hires Tom to catalog a library.

In America, young Martin and Mark fare badly. They thought they had bought land in Eden, but on their arrival, they find nothing more than a huddle of rude cabins in a swamp. Martin falls ill with fever, and when he recovers, Mark becomes sick. While he nurses his friend, Martin has time to realize the faults of his character and the true reason for the failure of his hopes. More than a year passes before the travelers are able to return to England.

John Westlock, having become interested in Jonas Chuzzlewit, befriends Lewsome, the young doctor from whom Jonas had secured poison. From Mrs. Gamp, who has nursed the physician through an illness, he learns additional details that make him suspect the son’s guilt in old Anthony’s death.

Old Martin seems to be in his dotage when his grandson and Mark arrive to see him at Mr. Pecksniff’s house, where he has been living. Martin attempts to reconcile with his grandfather and to end the misunderstanding between them, but Mr. Pecksniff breaks in to say that the old man knows the young man for a villain and a deceiver, and that he, Mr. Pecksniff, would give his life to protect the sick old man. Old Martin says nothing. Young Martin and Mark then travel to London, where they find Tom Pinch and Ruth. They also hear from John Westlock his suspicions regarding Jonas Chuzzlewit.

Jonas becomes desperate when Tigg forces him into a scheme to defraud Mr. Pecksniff. On their journey into Wiltshire, Jonas makes plans to dispose of Tigg, whom he hates and fears. After Mr. Pecksniff has agreed to invest his money in their company, Jonas returns to London and leaves Tigg to handle the transfer of securities. That night, disguised as a workman, he returns secretly to the village and attacks and kills Tigg as he is walking to his room at the inn. Leaving the body in the woods, Jonas takes a coach to London and arrives there at daybreak. Nadgett, ever watchful, has seen Jonas leave and return, and he follows the murderer when he tries to dispose of the clothing he had worn on his journey.

Old Martin Chuzzlewit, miraculously restored in body and mind, arrives unexpectedly in London for the purpose of righting many wrongs and turning the tables on the hypocritical Mr. Pecksniff. Having heard Westlock’s story, old Martin goes with him to confront Jonas with their suspicions. A few minutes later, police officers, led by Nadgett, appear to arrest Jonas for Tigg’s murder. The wretched man realizes that he is trapped and takes the rest of the poison he had obtained from Lewsome. The next day, old Martin meets with all concerned. It was he who hired Tom Pinch, and he now confesses that he has tested his grandson and Mary and found them worthy. When Mr. Pecksniff enters and attempts to shake the hand of his venerable friend, the stern old man strikes him to the floor with a cane.

The passing years bring happiness to the deserving. Young Martin and Mary are married, followed a short time later by Westlock and Ruth Pinch. Mark Tapley wins the mistress of the Blue Dragon Inn. Old Martin, out of pity, befriends Mercy Chuzzlewit. He himself rejoices in the happiness of his faithful friends, but there is no joy for Mr. Pecksniff. When news of Tigg’s murder reached the city, another partner in the shady enterprise ran away with the company funds, and Mr. Pecksniff was ruined. He has become a drunken old man who writes begging letters to Martin and Tom and who has little comfort from Charity, the shrewish companion of his later years.