Martin Chuzzlewit has been raised by his grandfather and namesake. Years before Martin senior took the precaution of raising an orphaned girl, Mary Graham, to be his nursemaid, with the understanding that she will be well cared for only as long as Martin senior lives. She thus has a strong motive to promote his well-being, in contrast to his relatives, who want to inherit his money. However, his grandson Martin falls in love with Mary and wishes to marry her, ruining Martin senior's plans. When Martin refuses to give up the engagement his grandfather disinherits him.

Martin becomes an apprentice to Seth Pecksniff, a greedy architect. Instead of teaching his students he lives off their tuition fees and has them do draughting work that he passes off as his own. He has two spoiled daughters, Charity and Mercy, nicknamed Cherry and Merry. Unbeknown to Martin, Pecksniff has taken him on in order to establish closer ties with his wealthy grandfather.

Young Martin befriends Tom Pinch, a kind-hearted soul whose late grandmother gave Pecksniff all she had in the belief that Pecksniff would make an architect and a gentleman of him. Pinch is incapable of believing any of the bad things others tell him of Pecksniff, and always defends him vociferously. Pinch works for exploitatively low wages while believing that he is the unworthy recipient of Pecksniff's charity.