Stiffy was yelling at him. "Come back, you danged old fool...." Suddenly the ground leaped and bucked beneath Meek's feet. The power plant reeled before his startled eyes and then, somehow, he was on his back, watching the dome wheel and weave above him. Fighting for breath that had been knocked out of him, he clawed his way to his knees, tried to stand erect, but the ground still was crawling with motion. It was like an earthquake, he told himself, startled that he could even think. But it couldn't be an earthquake. Juno didn't have earthquakes, there was no reason for Juno to have earthquakes. The little planetoid eons ago had cooled through and through, each rock, each strata had found its place. Juno was dead, dead as the reaches of space itself, and earthquakes don't happen on dead planets. Out of the corner of his eyes he saw the Prowler had backed out of the hole in the power plant, was standing with four legs spread wide, bracing himself. His long neck was stretched high in the air and the ugly, toothy head had the look of quick alertness. Meek gained his feet, stood tottering, keeping upright by some fancy footwork. The Prowler started toward him, legs gathering speed, heading down the street. With a hoarse whoop, Meek steadied himself, half crouched and held his breath, leaped, leaped so hard he almost vaulted over the beast's broad back. Sprawling, he scrambled into position astride the running robot, saw Stiffy leaping at him. Quickly he shot out a hand, grasped Stiffy and hauled him aboard. Ahead of them the crowd rushed for safety, leaving a broad avenue for the storming Prowler and his two riders. "Get the locks open," yelled Stiffy. "Here we come!" The crowd took up the shriek. "Get the locks open!" * * * * * The Prowler swept down the street, hoofs clattering like hammer blows. Ahead of them the inner lock swung open. As the Prowler bulleted into the entrance tunnel, the outer lock swung out and for a few wild seconds air screamed and howled, rushing from the city into the vacuum of space. In frantic haste, Meek and Stiffy worked with their helmets, getting them clamped down. Then they were out in the open, the gleaming city behind them. Less than half a mile away loomed a massive boulder towering a hundred feet or more above the level of the canyon floor. The Prowler made a beeline for it. "Oliver," yelled Stiffy, "that thing wasn't there before. Look, it almost blocks the canyon!" The boulder was black but it crawled with a greenish glow, a faint network of somber fire. The breath caught in Meek's throat. "Stiffy," he whispered. Behind him, Stiffy almost sobbed in excitement. "Yeah, I know. It's a meteor. And it's lousy with radium." "It just fell," said Meek, voice unsteady. "That's what shook up the place. Wonder is it didn't crack the dome wide open."