In the hot hills of Old Mexico, Operator 5 launched his great counter-espionage campaign against a plotting Asiatic horde which threaten to loose the entire barbarous guerrilla Southwest upon America! It was an attack that also combined modern Japanese mechanized warfare and dread tropical disease. As Operator 5 gathered his gallant border legions together to repel the most frightful invasion the world had ever seen, the very pages of history seemed turned back — when America was forced to make its last bloody stand on the hallowed ground of the Alamo!