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.
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 end, they enlist the help of the courageous "Kitty" (Evelyn Anders) and the street rats of London to track down these fifth columnists and stop an attempted sneak Nazi invasion of Britain. The story is solid, as are the performances and though the ending is just a little bit far-fetched, there is still plenty of intrigue to pass an hour well. Bruce has more to do here, and as always that makes the film more entertaining.