|Air date||July 6, 2011 (Canada)|
|Written by|| Paul Aitken|
|Directed by||John L'Ecuyer|
|Guest Stars|| Yannick Soulier as Marcel Guillaume|
Graham Abbey as Isaac Lowe
Kevin Jubinville as Roderick Dalewood
|Recurring||Lachlan Murdoch as Henry Higgins|
|Next||"Dead End Street"|
The disappearance of a visiting Parisian girl, Monique Poirier, thrusts Murdoch into an odd partnership with French Detective Marcel Guillaume, the real-life inspiration for the fictional Inspector Maigret. Brackenreid, meanwhile, ponders a political career.
Monique Poirier disappears while visiting her sister Sophie and brother-in-law at their Toronto hotel. Keys for rooms 409 and 212 are found in Monique's purse along with film but her camera is missing. They question the bellboy who was operating the elevator, states that he took Monique up to the fourth floor to get her camera but then she asked to be let off at the second floor. After searching Room 212, Roderick suggests Monique's disappearance may be connected to a letter found in her room. The letter, written in French, came from a gentleman caller, whom Monique sternly refused to see.
Constable Higgins alerts Detective Murdoch to a man who went into room 212 who turns out to be a Inspector Marcel Guillaume, who is attending a conference on international police cooperation in Montreal, has been hired by Monique's father to find her. Guillaume is shown the letter, remarking that the writing refers to the song Twenty-four Saint Vincent, which Murdoch realises is the address.
The gentleman caller, identified as David Bishop, is brought in for questioning. He admits to having met Monique on the train from Montreal and befriended her and she told him about the song. When they arrived in Toronto, she asked that he meet her at the hotel, but later on she strangely wanted nothing to do with him, which is why he persistently tried to see her.
Murdoch and Guillaume return to the hotel to question the Dalewoods again. After spotting a photo of the sisters on a boat, with Sophie looking less than pleased, Guillaume requests that they see the letters from Monique, to which Sophie expresses hesitancy given how private the letters are, until Guillaume convinces her that the letters may be the key to finding her sister. Reading the letter, they discover the concern Monique had for her sister. Murdoch returns to the station, where the hotel clerk arrives to inform him that he spotted Monique at the corner of Queen and Broadview, but she had different hair and clothes.
Later telling this to Guillaume, he asks if they have a photograph to show people in the area what Monique looks like. Brackenreid says they don't and it would take weeks for one to arrive from Paris. Detective Murdoch devises a way to transmit a photograph via telegraph, suggesting Mr. Poirier send one by telegraph and that they could then paint an enlarged facsimile of it. Then, a dead woman is discovered in a steamer trunk. Dr. Ogden notes that sulphuric acid had burned her face beyond recognition. At the City Morgue, Sophie identifies the body as Monique by her birthmark.
Back at the hotel, they find that the trunk came from room 214, right next to 212. Recalling that David Bishop works in a glass factory that handles sulphuric acid, they bring him back in, having found a lock of Monique's hair in his possession. David insists that Monique gave it to him and refuses their accusations. When asked where he was at the time of the death, he claims he was visiting his family. A telegram later confirms his alibi.
Murdoch remembers that sulfuric acid is found in batteries, like the ones in Roderick's electric car, but what's his motive? Then, Crabtree announces that a pawnbroker had turned in another of Monique's cameras. Developing the film, they find images of Roderick having sex with a bellboy which could be a motive for murder. They question Sophie about the true nature of her marriage. She admits that this was a perfect secret arrangement, as Roderick didn't want sexual relations and neither did she.
Murdoch and Guillaume then question Roderick about the night Monique disappeared, where he was having sex in room 214. He admits that Monique took photos of him and then ran off before he could get his clothes on, but Murdoch doesn't buy it. He formulates a theory that Roderick saw Monique run into room 212 and let himself in with his master key. And as he dismissed the bellboy, no one else can collaborate his alibi. Though Roderick insists that it's not true, Murdoch points out that Monique's purse was thrown right below room 212, most likely because she knew that Roderick was coming for her.
Guillaume is convinced it is Roderick but Murdoch points out inconsistencies. If Monique threw her purse out the window, why didn't Roderick retrieve it immediately? They speak to the pawnbroker, who says that a blond girl sold the camera to him and he knows that she lives at a boarding house on Degrassi Street. They bring in the girl, Victoria Wiggins, who insists that she innocently found the camera, but the policemen don't buy her story. Bringing her to the jail cells, where Roderick identifies her as Monique, to which Wiggins poorly claims ignorance.
Murdoch formulates a theory that the real Monique was murdered and Victoria Wiggins was brought in to pose as her long enough for her disappearance to be pinned on Roderick. Guillaume finds the thought of Sophie murdering her own sister to be absurd and insists that something else is going on. They check back with Crabtree and Higgins, who had finished more of the telefacsimile, and Murdoch recognises one of the women and returns with Guillaume to the hotel, finding the photograph of Sophie leaving Paris. However, he believes the woman in the picture who is smiling is the real Sophie but the woman who is not smiling is an impostor.
Showing "Sophie" the telefacsimile, they formulate the theory that she met the real Sophie on the ship from Paris and befriended her over the course of the voyage. Eventually, she learned of Sophie's arrangement with her wealthy fiancee who she wouldn't have to have sexual relations with and thus decided to take her place. "Sophie" claims they can't prove that but then Guillaume addresses her by her real name: Jacqueline Chiasson. She is wanted for murder ten months ago and the French consulate will be sending a picture of her to the station house. Jacqueline gives a basic confession, explaining that the life Sophie described seemed perfect to her, until Monique had come and threatened to expose her. That is why she had Victoria Wiggins impersonate her and why she kept David Bishop away from the hotel to prevent him from spoiling the charade.
- Murdoch speaks French, which he explains to Brackenreid was taught to him by Jesuits in New Brunswick.
- Murdoch invents a paint-by-numbers system to receive information and translate it into a photograph, across continents. Crabtree envisions the creation of devices known as “Tele Facsimile Machines”.
- Scottish inventor Alexander Bain worked on chemical mechanical fax type devices and in 1846 was able to reproduce graphic signs in laboratory experiments. He received British patent 9745 on May 27, 1843 for his "Electric Printing Telegraph."
- The Pantelegraph was invented by the Italian physicist Giovanni Caselli. He introduced the first commercial telefax service between Paris and Lyon in 1865, some 11 years before the invention of the telephone. Murdoch would have certainly read about both these invention.
- Chief Inspector Guillaume was head of the brigade spéciale of the Parisian police judiciaire and the prolific Belgian writer Georges Simenon based his Chief Inspector Jules Maigret on him in 75 novels and 28 short stories (from 1931-1972).
- Inspector Brackenreid is being pressured by a group of backers to support their plans to build a subway for Toronto. At about the time this episode was being written (late 2010 or early 2011), newly-elected Toronto mayor Rob Ford was backing a new subway line. 
- A roll of photographic film is found in a purse believed to belong to Monique. Detective William Murdoch instructs Constable George Crabtree to "have the film developed." Both policemen are known to be skilled photographers, but show no curiosity over the roll film, which is a highly unusual thing to see in the 19th century. Roll film that could be removed from the camera was a 20th century technology.
Yannick Soulier as Inspector Marcel Guillaume
Cristina Rosato as Sophie Dalewood / Jacqueline Chiasson
Kevin Jubinville as Roderick Dalewood
Carlyn Burchell as Monique Poirier / Victoria Wiggins
Michal Grajewski as David Bishop
Richard Binsley as Edwin Drury
Graham Abbey as Isaac Lowe
Robin Wilcock as Front Desk Clerk
Joe MacLeod as Elevator Operator
Craig Black as Rail Porter
Michael Dyson as Pawn Broker
Ace Hicks as Cecelia
Irena Angeloutsa as Angelique Guillaume
|Murdoch Mysteries Season 4|
| "All Tattered and Torn" • "Kommando" • "Buffalo Shuffle" • "Downstairs, Upstairs" • "Monsieur Murdoch" • "Dead End Street" • "Confederate Treasure" • "Dial M for Murdoch" • "The Black Hand" • "Voices" • "Bloodlust" • "The Kissing Bandit" • "Murdoch in Wonderland"|
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