Police Captain Howard was on a duty on a dark and stormy night when he and his fellow policeman heard fighting noises and cries for help. As they reached the crime scene it was too late, a man's body was lying on the street and a murderer has already escaped. Facing the dead end in the lack of evidence, Police Captain Howard includes in the investigation Shadow, a mysterious person who claims to be a private investigator fighting crime. The Shadow is asked to help solving this unusual case, but as the things begin to unravel, it turns out that the Shadow is more mysterious than the case.