1st of 2 graphic adventures from Thriller Picture Library #290, October 1959 - 32 pages.
Three days after Dunkirk, a top secret German document, believed to be Hitler's invasion plans, fell into British hands. To decipher the document and obtain its secrets, British Intelligence needed the German Code ZX913. Spy 13 was ordered to fly to France and obtain the code from a German printing works housed in a heavily guarded French castle.