"The Old Curiosity Shop" is about Nell Trent and her grandfather, who remains unnamed in the story. Nell is an orphan living with her grandfather in his shop. When her grandfather unintentionally gambles the shop away, he and Nell are forced to travel and live as beggars.
Nell is a lonely, uncomplaining orphan of about 13 or 14 years. Her grandfather is terrified of leaving her without an inheritance when he dies. He begins gambling in an attempt to earn more money for her.
When he gambles all of his money away to Daniel, the man evicts them both. Nell's grandfather suffers a mental breakdown, forcing Nell to care for him. Nell takes her grandfather away to live as a beggar while the others try to find her. By the time they find her, she has died and her grandfather stays at her grave to wait for her to return until he dies as well.
Though "The Old Curiosity Shop" is ostensibly about Nell and her grandfather, it could also be said to be about the people they encounter as they move through the story. There is Kit, who befriends Nell through working in the shop; Nell's wastrel brother, Frederick, who wants Nell to marry his friend Richard Swiveller for money he believes his grandfather has set aside for her; and the evil Daniel Quilp, who evicts Nell and her grandfather from their home and then offers to help Frederick and Richard with their plan.
Daniel knows that there is no money to be had but delights in the misery that will fall on all involved if the plan succeeds. A large portion of the story is dedicated to Frederick and Richard's attempts to find Nell, as well as Daniel's attempts to help them and hinder Nell's only friend, Kit.