A moment before he had localized the source of his uneasiness--an Earthman, following perhaps fifty paces behind him. The one quick glance Johnson had allowed himself told him his follower was above average in height, and lean--with the wiry, muscular command of himself that marked him as a man capable of well-coordinated action. He fought the rising force of the next "sand-blaster" boiling in from the desert, until he was unable to take a step against it. Then he moved behind a mud-packed arm projecting from the native dwelling at his right. Every building had one of these protecting arms added on; even the concrete buildings in the newer, Earth-built section of the city conformed to the custom. The sandstorms raged intermittently on Marlock through the entire nine month summer season, and could not be ignored, either by visitors or natives. Johnson huddled against the projection, but the sand whipped around the corner and pounded at his back. Fine grains sifted through his clothing and mingled with the clammy sweat of his body. He resisted the frantic urge to scratch his itching, tormented skin, for he knew the flesh would be rubbed raw in a minute and increase the irritation to maddening proportions. As the "sand-blaster" lost its intensity, he came out from his shelter and walked away as rapidly as the diminishing force of the wind would permit. If he could reach his office before his stalker closed in, he would be safe. Suddenly a second Earthman, a short length of pipe in his right hand, came out of a doorway across the street and ran toward him. Johnson realized that here was the source of the warning his intuition had sent--not the man behind him. * * * * * For a brief instant, he weighed the situation. The man was equipped for assault, but the chances were he was interested only in robbery. Johnson could probably save himself a beating by surrendering his money without resistance. He rejected the thought. A man had to live with his pride, and his self-respect; they were more necessary than physical well-being. Setting his shoulders firmly against the wall, he waited. The man slowed to a walk when he saw his intended victim on guard. Johnson had the chance to observe him closely. He was a short and dark man, heavy of bone, with the lower half of his face thickly bearded, and sweat making a thin glistening film on his high cheekbones. Abruptly a voice said, "I wouldn't touch him if I were you." Johnson followed the gaze of his near-attacker to his left where the lean man he had noted before stood with a flat blue pistol pointed in their direction. He held the pistol like a man who knew how to use it. "A gun!" the man in the street gasped. "Are you crazy?" "Better put it away--fast," Johnson warned his ally. "If the native police catch you with that gun, you're in bad trouble."