A short time before UK joined WW II german spys who call themselves the "Voice of Terror" broadcast over radio that they are about to bring a time of disaster and terror. Sherlock Holmes is asked by the "Inner Council" of the british intelligence agency to help them find the Nazis. Shortly after this, one of Holmes operatives is found with a german dagger in his back. Watson and Holmes are given a tip by the widow of the deceased, Kitty, and are able to find the spies, but their leader is able to escape. Kitty joins him in order to tell Holmes where the fugitive is and Holmes and Watson are able to find them with the Inner Council and several troops. Holmes then demasks the true villain and the real voice of terror: a german spy who had been working in the UK as a spy for twenty years.