"It began with an uncanny encounter on busy Seventh Avenue. Two men pass each other in the street, walking along calmly one minute -- struck down the next by a horrific fate. All over Manhattan, soundless detonations cut down prince and pauper alike.... One one man, Doc Savage -- scientist, adventurer and superman -- can penetrate the eerie enigma that threatens to bring the mightiest city on earth to its knees."--[P.4] of cover.