Why did a desperate man shave his head before going to Doc Savage headquarters, only to be struck down, his pulsing brain turned to inert stone? What sinister secret did his strange slaying silence? And how did a lizard-green shadow resembling Medusa appear on Doc's office wall? These are only some of the questions confronting the Man of Bronze as he pursues a grisly trail of petrified corpses to post-Prohibition Chicago, whose criminal underworld is being terrorized by a serpent-haired demon engaged in a seemingly senseless slaughter spree whose ultimate target will shake Doc Savage's men to their core. Suspects are many, but the clues baffling. Death is a constant menace, symbolized by the silhouette of a grim Gorgon. From the concrete canyons of Manhattan to the coal fields of Illinois, Doc Savage trails a phantom fiend the likes of which he has never before hunted. Or is he the one being hunted?