"Hurry," the detective urged, with a sidewise glance at Lysla. "And for God's sake don't get lost." "I won't. I'm heading for the left of the tube-tower. That's right, isn't it?" Zeeth nodded. "That's it. I'll tell you if I go wrong. Careful!" A Swamja was waddling toward them. Callahan hastily turned into a side street, making a detour to avoid the monster. For a while they were safe.... Lysla pressed close to Vanning, and he squeezed her arm reassuringly, with a confidence he could not feel. Not until now had he realized the vital importance of environment. On Mars or barren Callisto he had never felt this helplessness in the face of tremendous, inhuman powers--against which it was impossible to fight. Hopeless odds! But luck incredibly favored them. They reached their destination without an alarm being raised. Crouching in the shadows by the square where the space-ship lay, they peered at the three guards who paced about, armed and ready. "Only three," Lysla said. Vanning chewed at his lip. "Callahan, you know more about locks than I do. When we rush, get around to the other side of the ship and unlock the port. It may not be easy. The rest of us--we'll keep the Swamja busy." Callahan nodded. "I suppose that's best. We've only one gun." "Well--that can't be helped. Lysla, you go with Callahan." The blue eyes blazed. "No! It'll take all of us to manage the guards. I'm fighting with you." Vanning grunted. "Well--here. Take the gun. Use it when you get a chance, but be careful. Zeeth? Hobbs? Ready?" The two men nodded silently. With a hard grin on his tired face, Vanning gave the signal and followed the disguised Callahan as he walked toward the ship. Maybe the guards wouldn't take alarm at sight of one of their own race, as they thought. But the masquerade couldn't keep up indefinitely. The sentries looked toward the newcomers, but made no hostile move. One of them barked a question. Callahan didn't answer. He kept lumbering toward the ship, his masked face hideous and impassive. Vanning, at his heels, was tense as wire. Beside him, he heard Zeeth breathing in little gasps. Twenty paces separated the two parties--fifteen--ten. A guard croaked warning. His hand lifted, a gun gripped in the malformed fingers. Simultaneously Lysla whipped up her weapon and fired. Once--twice--and the Swamja cried out and dropped his gun, pawing at his eyes. Then-- "Let 'em have it!" Vanning snarled--and sprang forward. "Callahan! Get that port open!" * * * * * The masked figure hesitated, gave a whispered sound that might have been a curse, and then sprinted around the side of the space-ship. Vanning didn't see him. His shoulder caromed into the middle of the second guard, and the two went down together, slugging, clawing, kicking.