On a large-scale map in the military area command post, its progress could be watched as it was reported. The reports described a development of unbearable beam strength which showed up as a bulge in the cordon's roughly circular line. That bulge, which was the cordon itself moving back, moved outward and became a half-circle some miles across. It continued to move outward, and on the map it appeared like a pseudopod extruded by an enormous amoeba. It was the area of effectiveness of a weapon previously unknown on earth--the area where humans could not stay. Deliberately, the unseen moving thing severed itself from the similar and larger weapon field which was its birthplace and its home. It moved with great deliberation toward the small town of Maplewood, twenty miles from the border of the Park. Jeeps and motorcycles scurried ahead of it, just out of reach of its beams. They made sure that houses and farms and all inhabited places were emptied of people before the moving terror beams could engulf them. They went into the town of Maplewood itself and frantically made sure that nothing alive remained in it. They went on to clear the countryside beyond. The unseen thing from the Park moved onward. High overhead there was a dull muttering like faraway thunder, but it was planes with filled bomb racks circling above the starlit land. There were men in those planes who ached to dive down and destroy this separated fraction of an invasion. But there were firm orders from the Pentagon. So long as the invaders killed nobody, they were not to be attacked. There was reason for the order in the desire of the government to be on friendly terms with a race which could travel between the stars. But there was an even more urgent reason. The aliens had not yet begun to murder, but it was suspected that they had a horrifying power to kill. So it was firmly commanded that no bomb or missile or bullet was to be used unless the invaders invited hostilities by killing humans. Their captives--the crew of a helicopter--might be freed if aliens and men achieved friendship. So for now--no provocation! The thing which nobody saw moved comfortably over the ground between the park and Maplewood. In the center of the weapon field there was a something which generated the terror beam and probably carried passengers. Whatever it was, it moved onward and into Maplewood and for seven miles in every direction troops watched for it to move out again. Artillerymen had guns ready to fire upon it if they ever got firing coordinates and permission to go into action. Planes were ready to drop bombs if they ever got leave to do so. And a few miles away there were rockets ready to prove their accuracy and devastating capacity if only given a launching command. But nothing happened. Not even a flare was permitted to be dropped by the planes far up in the sky. A flare might be taken for hostility.