"It was feared for some time that some potential aggressor nation had managed somehow to get past the Kalahari guards and ferret out secret information—or else that there was already a fifth column among the technicians!"

No mention anywhere, of the Shadow Men!

I was scared stiff when I realized this. For those Shadow Men, it now seemed, had accomplished something the A-bomb had not been able to do; they had got inside the bombproof, killed Yount—and could easily have killed us all—and got out again.

"The experiments," said the announcer, "were of course carried out by the United Nations Security Council. The results have not been announced in every detail, but the world has been informed that complete security against the A-Bomb has been produced and will be available if ever there is another world war!"

But what about the Shadow Men? What good was the best bombproof if it could be entered so easily, and everybody inside it destroyed?

On the next day after our return I picked up a brief broadcast which I could easily have missed.

"It appears that there are still Japanese soldiers, hiding out on Guam, who do not know that the war is over. Ten Japanese, led by a Corporal Matzuku, surrendered yesterday to Guamian authorities! How they survived for almost four years is a mystery. They appear well fed."

I got this far and realized that I knew a great deal of what had happened, but not how. How we and the Guamian Japanese had been netted under the same bombproof, for instance—they on Guam, ourselves on Yataritas Beach, Cuba.

I had no explanation for the Shadow Men—except that nobody but the "vanishers", ourselves and the Japanese, so much as mentioned them. They were, I felt sure, outside the knowledge of the Security Council.

The Shadow Men were some manifestation—chemicals, or instantaneously acting disease germs?—of a potential enemy fifth column which had horned in on the Kalahari experiments.