The Adventures of Sherlock Holmes Professor Moriarty (George Zucco) has at long last been brought to trial for murder. But the 'Napoleon of Crime' is acquitted after the court finds a lack of sufficient evidence. Moments after the judge releases the defendant, Sherlock Holmes dashes into the courtroom with proof that will destroy Moriarty's alibi and send the professor to the gallows. Alas, he is too late and the criminal mastermind is set free. The Scarlet Claw Sherlock Holmes and Dr. Watson journey to Canada to attend a meeting of the Royal Canadian Occult Society in Quebec. Before long, they find themselves investigating a series of gruesome murders that the locals attribute to the legendary phantom marsh monster of La Morte Rouge. But Holmes suspects a master of disguise is the real killer, who might be anyone in the village. He contrives a clever trap courageously sets himself up to be the killer's next victim.