"Sherlock Holmes (Basil Rathbone) and Doctor Watson (Nigel Bruce) once again set out to foil the nefarious Moriarty (Lionel Atwill) -- and save humanity in the process. This time, they must prevent a Swiss-made bomb from falling into the hands of the Gestapo. Unfortunately, Moriarty has captured the bomb's inventor and intends to slowly bleed him to death unless he reveals the secret behind his handiwork."