Detective Sherlock Holmes (Basil Rathbone) and his trusty partner Dr. Watson (Nigel Bruce) travel to Quebec, Canada, where a small village has been terrorized by a series of grisly murders. Members of the Royal Canadian Occult Society, led by Lord William Penrose (Paul Cavanagh), believe that paranormal forces are to blame, but when Sherlock pinpoints the real culprit -- a vengeful actor -- he must track him down before he commits his next brutal act.