Taking its title from a phrase by defense council in an actual court case, THE SUSPICIONS OF MR. WHICHER details the real and fictional investigations of one of first London's real life detectives (the inspiration for Inspector Bucket in Charles Dickens' "Bleak House"). In THE MURDER AT ROAD HILL HOUSE, the discovery of the body of young Saville Kent in the house's out-building privy causes an uproar in the newspapers and the local judiciary, leading to calls in parliament for swift action to catch the murderer (the idea that someone can violate the safety of a "man's castle" being more of an outrage than the crime itself). London detective Jack Whicher (Paddy Considine, THE BACKWOODS) is sent down to Wiltshire to investigate the case and bring about a speedy resolution, with the reputation of the then-new detectives division at stake. He meets resentment from the local police – particularly the socially-conscious Superintendent Foley (Tom Georgeson, A FISH CALLED WANDA) who suspects the child's governess (Kate O'Flynn) – resistance from the Kent staff and family friends (who see his inquiries as meddling), and ridicule from the gutter press. The only person who does fully support Whicher's search for the truth is the dead boy's father Samuel Kent (Peter Capaldi, THE LAIR OF THE WHITE WORM) – the village's unpopular local squire rumored himself to be the murderer – despite what family skeletons Whicher dredges up since he believes his son's death is God's punishment for loving one child more than the others. Whicher's investigation leads him to suspect Constance (Alexandra Roach, A TRAP FOR CINDERELLA) – Kent's daughter from a previous marriage to a woman who died mad – who proves an unexpectedly formidable (possibly insane) opponent with a lack of physical evidence, vocal public opinion and witnesses who change their stories because of it, pandering local judges, a lack of support from the local police, and the shaken faith of Whicher's superiors in her favor when the case goes to court.

THE MURDER IN ANGEL LANE – like the remaining stories only "inspired by" Summerscale's books – finds Whicher living with his niece Charlotte (Angela Terence) and her newborn and working as a private inquiry agent (i.e. private detective) when not cultivating orchids. When he comes across well-bred Susan Spencer (Olivia Colman, herself a detective on TV's BROADCHURCH) in a rough part of town, he learns that she is looking for her pregnant niece Mary who followed the father of her child Stephen Gann (William Postlethwaite) to London. Despite still being considered mentally unfit for police work after the collapse of the Road Hill case, Whicher still has friends in the department and discovers that Mary has been the victim of an assault and Stephen seems the likely culprit. Whicher and Miss Spencer unfortunately arrive too late and discover that Mary has died from her wounds, but the whereabouts of the child she has given birth to in the last few hours is unknown. Whicher eventually tracks down the child, but to find Stephen he will have to delve into the history of the "cursed" Gann family: Stephen's father was hanged for the murder of Miss Spencer's father and his grandfather went mad. When Whicher comes to believe that Stephen is innocent, proving it might just send him to the madhouse (with some of his former colleagues warning him to stop interfering in the investigation and others to drop it for the sake of his sanity).

In BEYOND THE PALE, Whicher is boarding at a guest house run by widow Charlotte Piper (Nancy Carroll, AN IDEAL HUSBAND) when he is approached by Sir Edward Shore (Nicholas Jones, PHILOMENA) – the man who recommended his dismissal from the force after the Road Hill case – over a family matter. His son Charles (John Heffernan) is being troubled by a man named Asim Jabour (Adrian Quinton) over an "indiscretion" committed back in India, and now his his wife Katherine (Laura Frances-Martin) and twin boys are also under threat. Whicher takes to the docks in search of Jabour – who arrived on a ship as a lascar (East Indian sailor) – only to discover that he has been killed; however, he learns that Jabour arrived with his brother Roshan (Akshay Kumar, TV's HOMELAND) who still seems to be an imminent threat when Whicher learns from their fellow passengers that Jabour spoke of "Pratihinsa", or vengeance for a dishonor suggesting that Charles' indiscretion was something quite grave. Whicher desperately hopes to protect Charles' wife and children as well as Roshan since he comes to believe that the Shores will stop at nothing to silence the truth.

THE TIES THAT BIND finds Whicher taking on a divorce case for Sir Henry Coverly (Risteard Cooper, BATMAN BEGINS) whose wife Lady Jane (Helen Bradbury, QUARTET) has been seen in the company of Matthew Thorogood (Alex Robertson), a young man who seems to support himself through dubious and mysterious means. Thorogood proves quite willing to testify in the divorce case as he claims to be in love with Lady Jane. When he does not show up to give testimony, Whicher takes it upon himself to find Thorogood who has disappeared. When he discovers the man's dead body, the locals and the police suspect young chemist Linus Finch (James Northcote, WUTHERING HEIGHTS due to a public quarrel between the two men. When Whicher learns that the nature of this quarrel was over Thorogood fathering a child with Linus' sister Emma (Gwyneth Keyworth) who claims to have been betrothed to the dead man. When Whicher discovers that Thorogood had bespoke a wedding ring for Emma, he realizes that it would have made no sense for Linus to murder him and wonders about the dead man's true motives for Lady Jane. Rooming with the postmistress Ruth (Joanna Horton, FISH TANK) and her groomsman husband Joshua (Luke Thompson), he picks up the local gossip not on Thorogood but on the Coverlys and discovers a web of cruelty and manipulation that could indeed provide a motive for murder.

THE MURDER AT ROAD HILL HOUSE - the book "The Suspicions of Mr. Whicher" by Kate Summerscale and this TV adaptation – uses the facts of a true murder case to examine – which inspired elements of Mary Elizabeth Braddon's novel "Lady Audley's Secret" and Wilkie Collins' "The Moonstone" (as well as one of the stories of the Ealing Studios' ghostly portmanteau DEAD OF NIGHT) – to examine the science of detection in its infancy (with a primary difference between Whicher and the local police being the former's interest in motive), the misapplication of Darwinian theories, the belief that female madness was inherited from the mother, trial by public outcry, and reputations slandered by the press. Being the only story of the four films with the most factual basis, it is the best-plotted of them with a resolution that may seem unsatisfactory as far as formulaic British TV mysteries go but is truer to the facts. A little more time spent on Whicher's "congestion of the brain" would have been appreciated besides the "five years later" cut (especially since Considine looks rather wan even when his character is supposed to be in good health).

The subsequent three stories – only inspired by Summerscale's book – seem not to have been conceived with an overall continuity with some aspects that could prove jarring for the viewer who sits through all four films in a short amount of time. The victim in THE MURDER IN ANGEL LANE is called Mary Drewe, which was the name of one of the real-life figures in the Road Hill case while Whicher's presumably fictional niece is called Charlotte, which was the name of Whicher's real second wife who is introduced in BEYOND THE PALE and appears briefly in THE TIES THAT BIND. While the remaining episodes are just as twisty in plotting, they are not as substantive thematically; other than some light commentary on British colonial exploitation in its more unsavory forms, the curiously-titled BEYOND THE PALE is your typical Victorian adventure featuring "exotic" menace, while THE TIES THAT BIND gives us only a little insight into how even newer divorce laws still favored the husband (a man could get divorced based on proof of the wife's adultery whereas the wife had to prove adultery as well as incest, bigamy, cruelty or desertion). The remaining episodes also rather clumsily trots out Whicher's tragic backstory and often falls back on the people who hired him calling his mental health into question when things become complicated despite coming to him for his singular abilities in the first place. If there are to be more cases for Mr. Whicher, hopefully the next writers will not be afraid to develop his character more beyond Sumerscale's book and what little else is available about him.