Sherlock Holmes (Basil Rathbone) and Professor Moriarty (Lionel Atwill) engage in a battle of wits for control of a Switz inventor's newest bomb-sight creation. Holmes wants to safeguard it for the British while Moriarty isn't above selling out to the Nazis.

While no doubt many fans will be disappointed to see Holmes updated to the 1940s war-time setting, this particular film proves light-hearted fun which doesn't wallow in wartime propaganda as it might well have done. Dennis Hoey's Inspector Lestrade and Nigel Bruce's Dr. Watson do tend to steal the show as their characters bumbling methods consistently provide delightful comic relief. The sparring between Holmes and Moriraty is colorful and well thought out to boot. Atwill does well enough as Moriarty even if he's not as memorable as some others who played the role.

While this provides nothing especially new or thrilling for fans of the series, it is a wonderful escape from reality, somewhat appropriate for 1942 in my opinion, that mirrors many movie serial adventures of the 1930s and 1940s but boasts a more compact, less repetitive plot. And all this is done while still remaining true to the basic spirit of Sherlock Holmes.