Published in Jumbo Comics #6-#9, Feb 1939 - Aug 1939 - 15 pages
Major Hastings [of Military Intelligence] summons ZX-5 to tell him there has been a "serious leak of our army secrets" and the only clue they have is that a woman was "mixed up in it". He was to fly to South Chesterland to investigate. Meanwhile, a spy outside their door overhears and lets the woman know ZX-5 is coming.