The tiny South American republics of Santa Amoza and Delezon were at war when a mysterious, hooded figure - known only as The Inca Gray - appeared and began slaughtering citizens of both sides with a strange dust that brought instant, writhing death. Doc Savage and his mighty crew rush to the dense Amazonian forest in hopes of saving lives, but all they find when they arrive is a firing squad-ready to execute The Man Of Bronze!

First published in Doc Savage Magazine # 32 October 1935 - written by Lester Dent (and/or Harold A. Davies?)