Though it is not based on any Conan Doyle story, The Scarlet Claw is regarded by Baker Street aficionados as the best of Universal's Sherlock Holmes series. Holmes (Basil Rathbone) and Watson (Nigel Bruce) journey to Canada to investigate a series of mysterious murders. All the victims have been found with their throats ripped out (yecch!). Halfway through the film, Holmes deduces that the culprit is a demented actor, wreaking vengeance on those who've wronged him in some way or other. The actor is a master of disguise, and could be anyone in the village -- from the constable to the postman to the reclusive, violence-prone innkeeper (Arthur Hohl). Alas, the publicity photos sent out with The Scarlet Claw gave away the identity of the killer -- something we have no intention of doing here.
by Hal Erickson synopsis