son from his second marriage, she immediately becomes Whicher's prime suspect. It is discovered that Constance and her younger brother William Saville-Kent (Charlie Hiett) hate their stepmother Mary (Emma Fielding) — who had, in fact, been employed as their former nanny, with whom their father had had an affair while their mother was dying. He visits a schoolmate of Constance, Emma Moody, who tells him that Constance enjoyed hurting Saville. As the circumstantial evidence builds, Whicher arrests Constance, he having been convinced that she had killed her half-brother out of revenge against her father for his treatment of her mother and his neglect of her and William, but he fails to get a confession from her or William. Whicher desperately seeks Constance's missing nightdress, which he believes she wore while murdering her half-brother, as the key evidence to proving her guilt. He suspects Constance disposed of the blood-soaked nightdress after the murder, and tricked everyone into believing it had been lost by the washerwoman. However, he cannot find the nightdress and at her trial, her lawyer discredits Whicher's case by wilfully misrepresenting it. Emma Moody is called as a witness, but she lies and states that Constance adored her half-brother, and Constance is acquitted. Whicher accuses Mr. Kent of abetting the wrongful acquittal. Whicher's reputation is destroyed. He suffers a breakdown and leaves the police force. Five years later, in 1865, Constance confesses her guilt to a clergyman, the Rev. Arthur Wagner (Antony Byrne), and is re-tried. In court the Rev. Wagner gives a declaration that he must withhold any information on the grounds that it had been received under the seal of "sacramental confession". At the same time it is revealed that Superintendent Foley had withheld evidence from Whicher during the original investigation. This time Constance Kent admits her guilt, but refuses to corroborate Whicher's theory that her brother was also involved in the murder. Constance Kent is sentenced to death. However, viewers are informed by means of captions that due to public outcry after the trial the sentence is commuted to life in prison, that she is released after serving twenty years, and that she emigrates to Australia where she dies at the age of 100. Cast Paddy Considine ... Detective Jack Whicher Peter Capaldi ... Samuel Kent Tom Georgeson ... Superintendent Foley William Beck ... 'Dolly' Williamson Emma Fielding ... Mary Kent Tim Pigott-Smith ... Commissioner Mayne