He moved more cautiously now, stepping gingerly from rung to rung up the swaying ladder. The cleft widened; he was near the top. He paused. There was not the slightest sound. But Hilary was taking no chances. With infinite slowness he raised his head over the matted underbrush that masked the entrance. For the moment he could see nothing in the pitchy blackness. Then a dim shape loomed to one side. From within it there came a tiny hum, intermittent, almost inaudible. Hilary knew what that was: a transmitter. Even then the fatal message was winging through the ether. He did not hesitate. He lofted to the ground with one quick heave, steadied on his swaying feet as the automatic flashed into his hand. "Throw up your hands, Mercutian," he shouted at the dimly-perceived bulk. "I have you covered." He tensed, straining his ears for any movement that might locate the hidden foe. The tiny humming ceased abruptly. There was painful silence. "Don't try--" Hilary commenced. He stopped, swerved his body suddenly to one side. A red glow had warned him. The hurtling ray scorched past him with a crackling blaze. Hilary was off balance, teetered, and went down with a crash into the thorny underbrush, his automatic exploding into sharp flame. * * * * * A hoarse guttural laugh came from the flier. "Got you that time, Earth dog," the invisible Mercutian taunted. There was silence. Another belt crashed from the ship, heaved the ground under its impact. Another and another. Still no break in the silence, no cry. The Mercutian muttered to himself: "The dog is dead, all right." He peered out cautiously. The underbrush was black, sullenly quiet. Great swaths showed where the rays had swept the Earth. With a hoarse chuckle the grotesque giant climbed over the side of his ship. A search beam swung in his hand. He was in deep shadow. He swung the beam in a short arc. There was nothing, only matted vegetation. There was one thick thorny bush he noted, however, extending its bulk behind the bow of the ship. He stepped out a bit, away from the flier's shadow, and swung his beam directly at it. The invisible ray pierced through the interlacing twigs with ease. It picked out a prone figure, lying with arm extended. The Mercutian chuckled again, but the chuckle changed almost immediately to a throaty cry of alarm. With a swiftness that went incongruously with his awkward bulk, his free arm dropped for his hand ray. There was a sharp burst of flame, a staccato bark. The Mercutian staggered, swayed with sullen pain-widened eyes, and pitched headlong forward. * * * * *