A bank carriage is robbed but the thieves' getaway ride is sabotaged by an apparent drunk, who loosens the horse's reins. One of the thieves then kills their driver before running off.
The next morning, as the corpse is found, a man claiming to be Sherlock Holmes introduces himself to Murdoch and Crabtree. The man is identified as David Kingsley, who suffers from a delusion of identity and insists that Professor Moriarty is behind the robbery. Attempts to coax him back to himself prove unsuccessful, even when they bring in Sir Arthur Conan Doyle to prove that Sherlock is fictional, as David gives a logical way for Sherlock to survive his last encounter with Moriarty.
Eventually, it is determined that the thieves were looking for a valuable diamond they've spent ten years searching for, about the same time David was committed. With Dr. Ogden's help, Murdoch is able to coax David back to himself by telling him that he witnessed his stepfather's murder, snapping him out of his delusions. David explains that his stepfather read to him many Sherlock Holmes stories and disguised one story about the Star of Tarsus as part of the series, as hint as to where the diamond was.
Murdoch and Brackenreid drop by David's old house to find David's uncle and accomplice searching through his old model boat in search of the diamond. Though the thieves surrender with Brackenreid holding a rifle. However, David also arrives, brandishing a pistol, determining to take vengeance for his stepfather's murder. Murdoch is able to convince him to stand down by encouraging him to return to his Sherlock persona, reminding him of Sherlock belief in justice and the rule of law.
The diamond is later found in the creek where David played with his boat, which David finds. Murdoch tells him that the Persian consulate is willing to pay a substantial sum for its recovery and asks who they should thank. David says they should thank Sherlock Holmes.
- Sherlock's real name is David Kingsley, a former patient of the late Dr. Roberts.
- David Kingsley as Sherlock gives Arthur Conan Doyle a way to bring his famous hero back to life.
- Arthur Conan Doyle returns to meet his creation.
- David Kingsley returns to the Provincial Lunatic Asylum, to undergo hypnosis, administered by Dr. Ogden and observed by Murdoch.
- This episode takes place in Toronto 1900 – the Victorian Era (1837-1901) when Victoria, Queen of the United Kingdom of Great Britain and Ireland, Defender of the Faith, and Empress of India, rules the British Empire.
- The name of the episode is a reference to A Study in Scarlet, the first Sherlock Holmes novel.
- Michael Rhoades who plays Oscar Kingsley first appeared in Season 1 as John Delaney in Let Loose the Dogs.
Michael Rhoades as Oscar Kingsley
Michael Copeman as Bank Manager
Stevel Boyle as Sebastian Moran
Andrew Loder as Guard
Barry Flatman as Guard
Ty Kostyk as Machinist
Costa Kamateros as Getaway Driver
Maxi Jennings as Flower Girl
|Murdoch Mysteries Season 6|
|"Murdoch Air" • "Winston's Lost Night" • "Murdoch On The Corner" • "A Study in Sherlock" • "Murdoch Au Naturel" • "Murdoch and the Cloud of Doom" • "The Ghost of Queen's Park" • "Murdoch in Ladies Wear" • "Victoria Cross" • "Twisted Sisters" • "Lovers in a Murderous Time" • "Crime and Punishment" • "The Murdoch Trap"|
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