Summer 1860, a country house and a young boy is found dead. Celebrated detective Mr Whicher is sent to solve the murder. Over twenty years later, still haunted by the case and its outcome, Whicher visits the imprisoned murderess, troubled by fears that the real truth was not uncovered. As the past is replayed, they start to question the nature of truth, the desire for certainty and the possibility of redemption. Based on the bestselling book, this compelling adaptation imagines a gripping new conclusion to a dark Victorian mystery.