An armored truck carrying $100,000 in cash, is lured off the highway on a foggy night and crashes in the blinding rain. The money is stolen and the driver is dead - but the guard escapes from the crash. His sister reaches Boston Blackie, but then the guard is murdered not long after Blackie arrives. The problem is, Boston Blackie looks guilty of the crime, since he was found unconscious with the murder weapon in his hand...