Holmes, retired to Sussex, is drawn into a last case when his arch enemy Moriarty arranges with an American gang to kill one John Douglas, a country gentleman with a mysterious past. Holmes' methods baffle Watson and Lestrade, but his results astonish them. In a long flashback, the victim's wife tells the story of the sinister Vermissa Valley.
Arthur Wontner
as Sherlock Holmes
Lyn Harding
as Prof. Moriarty
Leslie Perrins
as John Douglas
Ian Fleming
as Dr. John Watson
Charles Mortimer
as Insp. Lestrade
Minnie Rayner
as Mrs. Hudson
Michael Shepley
as Cecil Barker
Jane Carr
as Ettie Douglas
Ben Welden
as Ted Balding
Roy Emerton
as Boss McGinty
Wilfrid Caithness
as Col. Sebastian Moran
Conway Dixon
as Ames
