Andrew Davies's adaptation of the classic Charles Dickens tale of hardship and struggle in 1820s London. The Dorrit family has spent years in a debtors' prison due to the financial mess in which father William (Tom Courtenay) managed to land himself as a youth. Youngest daughter Amy (Claire Foy), known as Little Dorrit, finds work with the wealthy Mrs Clenham (Judy Parfitt) but knows that her father will, in all probability, spend the remainder of his life in gaol.

However, when Arthur Clenham (Matthew Macfadyen), recently returned from abroad, comes to suspect that his late father was in part responsible for the Dorrits' plight, he becomes determined to make amends. But as he continues to delve into the mysteries of the Dorrits' and his parents' shared past, he is unaware that his own mother's house has been placed in peril by the arrival of a sinister stranger.