Old Martin Chuzzlewit, is very rich and very old; he is convinced that his relatives are only interested in his money and cannot wait for him to die so that they can inherit his fortune. Chuzzlewit develops a scheme to thwart what he thinks are his relatives designs: he takes in an orphan named Mary, whose job is to be his nursemaid. Mary will be well taken care of and live comfortably only so long as old Martin Chuzzlewit is alive, but as soon as he dies, she will be thrown out onto the streets without a penny. In this way, old Martin Chuzzlewi thinks that he can motivate Mary to take good care of him and help keep him alive, in contrast to his greedy relatives who he thinks want him dead.
Chuzzlewit's plans are thwarted when his grandson and heir, Martin Chuzzlewit Junior, falls in love with Mary and wishes to marry her. Fearing that Mary will therefore have a reason to benefit from his death, the old man orders his grandson to break off the engagement, but the younger Martin Chuzzlewit refuses. In a rage, the old man disinherits his grandson, who must then fend for himself in a hostile and greedy society.
The young Martin Chuzzlewit tries to make his way in the world by becoming an apprentice to the villainous Mr. Pecksniff, a relative of his grandfather. Pecksniff is one of Dickens' great villains: he is talentless, full of himself, falsely pious. He periodically takes in students, offering to teach them architecture and then lives off of their tuition fees while teaching them nothing and stealing their ideas.
Pecksniff has two daughters, Mercy (Merry) and Charity (Cherry). Charity is very much like their father and exhibits none of the good qualities for which she is named. Her sister Merry is at first giggly and flighty, but later loses her shine when she marries an abusive man, Jonas Chuzzelwit (who is the nephew of Old Martin Chuzzlewit).
service of Pecksniff, Chuzzlewit befriends Pecksniff's servant Tom Pinch, an idealistic and innocent young man who is in some ways the main character of the novel.
When the elder Martin Chuzzlewit hears that his grandson is apprenticing to Mr. Pecksniff, he demands that Pecksniff kick the younger Chuzzlewit out immediately, which he does. The old man then moves in with his relation, together with his nursemaid Mary, and promptly falls under the complete control of the villainous Pecksniff and his daughters. Meanwhile Tom Pick also falls in love with Mary (Something About Mary?) but refrains from expressing his feelings because he knows that his friend Martin is in love with her too.
Pinch idolizes Mr. Pecksniff, but eventually comes to see him for what he really is: an avaricious user. Pecksniff then dismisses his servant. Pinch eventually finds new employment with the mysterious Mr. Fibs, whose true identity is not revealed until the end of the book.
