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.
Meanwhile, Kit, having lost his job at the curiosity shop, has found new employment with the kind Mr and Mrs Garland. Here he is contacted by a mysterious ‘single gentleman’ who is looking for news of Nell and her grandfather. The ‘single gentleman’ and Kit’s mother go after them unsuccessfully, and encounter Quilp, who is also hunting for the runaways. Quilp forms a grudge against Kit and has him framed as a thief. Kit is sentenced to transportation. However, Dick Swiveller proves Kit’s innocence with the help of his friend the Marchioness. Quilp is hunted down and dies trying to escape his pursuers. At the same time, a coincidence leads Mr Garland to knowledge of Nell’s whereabouts, and he, Kit, and the single gentleman (who turns out to be the younger brother of Nell’s grandfather) go to find her. Sadly, by the time they arrive, Nell has died as a result of her arduous journey. Her grandfather, already mentally infirm, refuses to admit she is dead and sits every day by her grave waiting for her to come back until, a few months later, he dies himself.