The Scarlet Claw is one of the spookiest, finest, and longest films in the series, as well as being a particular favourite of mine. It borrows some elements from The Hound of the Baskervilles and it features plenty of gruesome deaths, fog-enshrouded bogs, some great character acting, along with a very clever murderer with a talent for disguise that rivals even the great detective's himself. Nigel Bruce has some few fun scenes, especially one where an inebriated Watson tries to prise information from the postman and other patrons in the hotel bar…

Synopsis

The films opens on a foggy night in the French Canadian village of La Mort Rouge, with the local church bells peeling forth a cry of help from Lady Penrose. She's been fatally stabbed and now clutches the rope, desperately ringing the bells in alarm as her life slips away. The priest answers her call, along with Potts the postman but they arrive too late to save her.

Sherlock Holmes and Dr. Watson are in Canada attending a conference on the occult when the chairman, Lord Penrose, receives a message that his wife has been murdered. Penrose is convinced that his wife was killed by supernatural forces. Holmes and Watson are about to return to England when Holmes receives a telegram from Lady Penrose, issued before her death, asking for help as she fears for her life. Holmes decides to investigate.

Holmes and Watson arrive at the remote village, where they go to see Lord Penrose and examine the body of his murdered wife. The claw-like wounds on Lady Penrose could be supernatural, animal or man-made, and Holmes recognises Lady Penrose as the former actress Lillian Gentry. Holmes and Watson's presence is not welcome in the Penrose household however, so they soon leave and go to see the local police sergeant to discuss the case.

After chatting to Sergeant Thompson about the murder, Holmes and Watson check into Journet's, the village's hotel. Holmes questions the nervous landlord, Emile Journet, and his frightened daughter Marie about the murder of Lady Penrose but Journet denies any involvement. Holmes asks Watson to spend the evening in the hotel bar questioning the patrons, while he slips out and investigates the marshes surrounding the village.

Watson has a fine time in the hotel bar, at the end of which he's regaling all the villagers with tales of his adventures with Holmes. Out on the marshes, Holmes runs into the monster of La Mort Rouge who leaves behind a torn piece of shirt fabric covered in luminescent paint. When Sergeant Thompson tells Watson that Holmes is on the marshes alone, the doctor races out to find him, only to run into the monster himself – “a roaring furnace, spitting fire in all directions” – who pushes him into a boggy hole.

As Watson recuperates from the chill he caught on the marshes, Holmes goes to see Sgt. Thompson and they study the shirt fabric. The local shop keeper tells says that the shirt it came from belongs to the housebound Judge Brisson. Holmes and Watson go to see the isolated Brisson in the morning and Holmes soon sees through his pretence of being a cripple. The judge gives Holmes the clue to who has his old shirt, a man who did some gardening work for him called Tanner.

Holmes, Watson and Sgt Thompson go to find Tanner at his hideout on the river where they find a luminescent shirt that explains the flame-spitting monster of La Mort Rouge, but before they can arrest him, he escapes out of the window and into the river below. Watson and the Sgt think they've shot and killed him but no such luck. Holmes found a half-torn photograph of Lady Penrose in Tanner's room, and goes off to break into Lord Penrose's house, where he finds the other half of the torn photo.

Lord Penrose explains that a man called Alistair Ramson murdered a fellow actor in his wife's acting company in a jealous rage. Ramson has escaped from prison and is now in La Mort Rouge – in character as Tanner, and he most probably has other characters to hide behind as he wreaks revenge for his punishment. Ramson killed Lady Penrose is now after Judge Brisson, the magistrate who sent him to gaol.

Holmes arrives at the Brisson's home a fraction too late, Ramson disguised himself as the housekeeper, broke in, and killed the old judge with a five-pronged garden weeder. Holmes phones Sgt Thompson and tells him of the latest murder, whilst he goes to the hideout on the river to look for Ramson. He finds Ramson who holds him at gunpoint and explains everything, and he's about to tell Holmes who his third victim is to be, before Watson falls on the stairs and comes to Holmes' rescue. Ramson escapes again, this time through a secret panel.

Holmes deduces that Emile Journet is the next victim, he was a former prison guard of Ramson's. However, Journet has gone into hiding, aware that the killer is after him. Ramson kills Marie Journet for not revealing her father's whereabouts as Holmes searches for Journet's hiding place. When they find Journet, Holmes tells him of his Marie's murder and manages to convince Journet to help set a trap for Ramson.

Back in Journet's, Holmes and Watson announce that after failing to catch the killer, they are to return to England. Journet has come out of hiding and is also in the hotel bar, he lets it be known that he's going to the church across the marsh to offer a prayer for Marie. Ramson attacks Journet out on the marsh, only to discover that it's Holmes in disguise. The two men struggle, Ramson escapes but only to be caught and killed by Journet with his own weapon; the five-pronged garden weeder.

The film ends with Holmes and Watson travelling along in a open top car on their way back to England, with Holmes quoting Churchill as he makes a speech extolling the virtues of Canada, “the linchpin of the English-speaking world”.