The Old Curiosity Shop tells the story of Nell Trent, a beautiful and virtuous young girl of "not quite fourteen". An orphan, she lives with her maternal grandfather (whose name is never revealed) in his shop of odds and ends. Her grandfather loves her dearly, and Nell does not complain, but she lives a lonely existence with almost no friends her own age. Her only friend is Kit, an honest boy employed at the shop, whom she is teaching to write. Secretly obsessed with ensuring that Nell does not die in poverty as her parents did, her grandfather attempts to provide Nell with a good inheritance through gambling at cards. He keeps his nocturnal games a secret, but borrows heavily from the evil Daniel Quilp, a malicious, grotesquely deformed, hunchbacked dwarf moneylender. In the end, he gambles away what little money they have, and Quilp seizes the opportunity to take possession of the shop and evict Nell and her grandfather. Her grandfather suffers a breakdown that leaves him bereft of his wits, and Nell takes him away to the Midlands of England, to live as beggars.
Convinced that the old man has stored up a large and prosperous fortune for Nell, her wastrel older brother, Frederick, convinces the good-natured but easily led Dick Swiveller to help him track Nell down, so that Swiveller can marry Nell and share her supposed inheritance with Frederick. To this end, they join forces with Quilp, who knows full well that there is no fortune, but sadistically chooses to 'help' them to enjoy the misery it will inflict on all concerned. Quilp begins to try to track Nell down, but the fugitives are not easily discovered. To keep Dick Swiveller under his eye, Quilp arranges for him to be taken as a clerk by Quilp's lawyer, Mr. Brass. At the Brass firm, Dick befriends the mistreated maidservant and nicknames her 'the Marchioness'. Nell, having fallen in with a number of characters, some villainous and some kind, succeeds in leading her grandfather to safety in a far-off village (identified by Dickens as Tong, Shropshire), but this comes at a considerable cost to Nell's health.
On Christmas Eve, around 1812, Pip, an orphan who is about seven years old, encounters an escaped convict in the village churchyard, while visiting the graves of his parents and siblings. Pip now lives with his abusive elder sister and her kind husband Joe Gargery, a blacksmith. The convict scares Pip into stealing food and a file. Early on Christmas morning Pip returns with the file, a pie and brandy. During Christmas Dinner that evening, at the moment Pip's theft is about to be discovered, soldiers arrive and ask Joe to repair some shackles. Joe and Pip accompany them as they recapture the convict who is fighting with another escaped convict. The first convict confesses to stealing food from the smithy.
A year or two later, Miss Havisham, a wealthy spinster who still wears her old wedding dress and lives as a recluse in the dilapidated Satis House, asks Mr Pumblechook, a relation of the Gargery's, to find a boy to visit her. Pip visits Miss Havisham and falls in love with her adopted daughter Estella. Estella remains aloof and hostile to Pip, which Miss Havisham encourages. Pip visits Miss Havisham regularly, until he is old enough to learn a trade.
Joe accompanies Pip for the last visit, when she gives the money for Pip to be bound as apprentice blacksmith. Joe's surly assistant, Dolge Orlick, is envious of Pip and dislikes Mrs Joe. When Pip and Joe are away from the house, Mrs Joe is brutally attacked, leaving her unable to speak or do her work. Orlick is suspected of the attack. Mrs Joe becomes kind-hearted after the attack. Pip's former schoolmate Biddy joins the household to help with her care.