The daring detective dons his deerstalker and heads for America with Dr Watson in tow. They are out to stop dastardly Nazi spies stealing a vital microfilm document which has fallen into the hands of a beautiful socialite. However, they find she has already been kidnapped by the conniving villains. Mystery, starring Basil Rathbone, Nigel Bruce, Henry Daniell, Marjorie Lord and George Zucco.

In World War II, a British secret agent carrying a vitally important document is kidnapped en route to Washington. The British government calls on Sherlock Holmes to recover it.