Rolf snapped his weapon overhand at the Frog's hairless skull. The fish-bellied alien ducked but his expoder swung off the target momentarily. In that instant Rolf launched himself from the open framework of the slowly diving glider, full upon the Venusian. They went down, Rolf swinging his fist like a hammer. He felt the Frog go limp and he loosed a relieved whistle. Now with a rocket flyer and the guard's rifle expoder in his grasp the problem of escape from the inner caverns was solved. He would rescue the girl, stop at the Forbidden City for Mark Tanner, and blast off for the upper crust forty miles and more overhead. He knelt over the prostrate Venusian, using his belt and a strip torn from his greenish tunic to bind the unconscious man. The knots were not too tight, the man could free himself in the course of a few hours. He shrugged his shoulders wearily and started to get up. A foot scraped on stone behind him. He spun on bent knees and flung himself fifty feet to the further side of the narrow gulch with the same movement. Expoder needles splintered the rocks about him as he dropped behind a sheltering rocky ledge, and he caught a glimpse of two green-clad men dragging the bronze-haired body of the girl he had come to save into the shelter of the flyer. A green bulge showed around the polished fuselage and Rolf pressed his captured weapon's firing button. A roar of pain came from the wounded man, and he saw an outflung arm upon the rocky ground that clenched tightly twice and relaxed to move no more. The outlaw weapon must have been loaded with a drum of poisoned needles, the expoder needles had not blasted a vital spot in the man's body. The odds were evening, he thought triumphantly. There might be another outlaw somewhere out there in the badlands, but no more than that. The flyer was built to accommodate no more than five passengers and four was the usual number. He shifted his expoder to cover the opposite end of the ship's squatty fuselage. And something that felt like a mountain smashed into his back. He was crushed downward, breathless, his eyes glimpsing briefly the soiled greenish trousers of his attacker as they locked on either side of his neck, and then blackness engulfed him as a mighty sledge battered endlessly at his skull. * * * * * This sledge was hammering relentlessly as Rolf sensed his first glimmer of returning light. There were two sledges, one of them that he identified as the hammering of blood in his throbbing temples, and the other the measured blasting pulse of rocket jets. He opened his eyes slowly to find himself staring at the fine-crusted metal plates of a flyer's deck. His nose was grinding into the oily muck that only undisciplined men would have permitted to accumulate.