This mini-series tells the story of Amy Dorrit (Claire Foy), who spends her days earning money for the family and looking after her proud father (Sir Tom Courtenay), who is a long term inmate of Marshalsea debtors' prison in London. Amy and her family's world is transformed when her boss' son, Arthur Clennam (Matthew Macfadyen), returns from overseas to solve his family's mysterious legacy and discovers that their lives are interlinked.