After the death of his father leaves his family destitute, young Nicholas Nickleby must navigate a corrupt and indifferent society to protect his mother and sister from his predatory uncle. Nicholas seeks employment and stability, but he is constantly thwarted by the machinations of his cruel uncle, Ralph Nickleby, and the systemic abuses of the institutions he encounters. The narrative follows a sprawling, third-person perspective that tracks Nicholas's moral development as he traverses the landscape of early Victorian England. He faces physical hardship, professional exploitation, and social injustice while attempting to maintain his integrity against those who seek to profit from the suffering of others.

Readers and critics frequently highlight the balance between the novel's dark social commentary and its moments of exuberant, Dickensian humor. Discussion often centers on the effectiveness of the grotesque villains, such as Wackford Squeers, who serve as focal points for the author's critique of educational neglect. Many observers note that while the pacing is occasionally slowed by the sheer volume of subplots, the character development of Nicholas provides a consistent emotional anchor. The work is widely regarded as a pivotal example of the author's ability to blend moral earnestness with a sprawling, multi-layered narrative structure.