The rush of treads and whine of brakes from the street interrupted him, sending him to the window with gun ready. The screen-creature, still alive with the almost unkillable vitality of those alien things, had dragged itself together to cover the opening again. Nick was careful not to touch it. He peered out, knowing that to the men climbing from the armored half-track the window would appear dark. The screen-creatures passed light in one direction only. As quietly as possible he closed the sliding panel at the top of the ramp and pushed in the locking plug. "Remember, get the old man alive. Stun him if necessary, but alive. That's orders from The Man himself." Nick recognized Colonel Hammer's voice. The search must be tightening if the commandant himself took charge of a patrol. They were after Professor Jones and his daughter, but Nick knew that he too would be shot on sight. This time he was with the hunted instead of the hunters. The girl's face went white as he drew his sheath knife. Then she stared uncomprehendingly as the blade slit her bonds instead of her throat. "Over the roofs," he whispered. "Which way out?" She pointed, still uncertain of his intentions. A big man in a uniform like Nick's own lay sprawled on the floor of the adjoining room, a black circle between his eyes. Nick spared him just one glance. And then he understood the sticky-moist splotch he had encountered in the street. The man with the straggly beard had caused it, bleeding his life away through the gaping rent in his chest. The girl ignored Nick's ready pistol and ran to the low couch on which the old man reclined. "Dad!" she called softly, shaking his shoulder. "Dad!" Nick pulled her away and shook his head. Jackson Jones, the first man to reach Mars, was dead. "Shoot that panel down!" someone yelled from the ramp. "He's in there!" "Wanna get took by the back-blast?" another voice complained. "Stand back." "Which way?" Nick asked quietly. The girl darted to a window and Nick caught his breath as she reached toward the guarding screen-creature. Then he stared for, instead of killing her with its strange powers, the rubbery, no-color, living stuff flowed back into grooves in the edge of the stone. Susan gave one last backward glance at her father's body and scrambled through. Nick followed nervously and sprawled beside her on a narrow roof ledge. She touched the screen-creature again and it closed with a silent, oily motion. "It felt my thoughts," she whispered. He dragged her to her feet and they ran through the dim starlight, climbing across the uneven roofs, leaping the chasms between buildings in the darkness. Excited yells as the patrol broke through the panel and found the two bodies speeded them onward. The girl held her own, keeping the fast pace Nick set, although a few times he had to help her swing her slender body from a lower roof to a higher one.