England, at the start of World War Two. Mysterious wireless broadcasts, apparently from Nazi Germany are heard over the BBC. They warn of acts of terror in England, just before they take place. Baffled, the Defense Committee call in Sherlock Holmes.

Basil Rathbone
as Sherlock Holmes

Nigel Bruce
as Doctor Watson

Evelyn Ankers
as Kitty

Reginald Denny
as Sir Evan Barham

Thomas Gomez
as R.F. Meade

Henry Daniell
as Sir Anthony Lloyd

Montagu Love
as General Jerome Lawford

Olaf Hytten
as Admiral Sir John Fabian Prentiss

Leyland Hodgson
as Captain Roland Shore

Mary Gordon
as Mrs. Hudson
CinemaSerf
This time, our detective duo are brought in to help the solve an intriguing wartime mystery. A voice on the radio is announcing details of an impending disaster, and the "Inner Council" led by Reginald Denny's "Sir Evan" is desperate to thwart these ruthless and effective acts of sabotage. To that e...