Published in Jumbo Comics #1-#6, Sep 1938 - Jan 1939 - 19 pages
After a plane from the country of Transovania flies over a city in the Kale Valley of the neighboring nation of Chesterland and drops a bomb destroying a munitions factory, war is underway. ZX-5 is summoned to a Major Jason's office and given the mission to sneak into Transovania to learn where the troops are.