Jim looked up at the pale moon above their heads as they walked toward the parking lot. "I hope so," he said. "We will soon know whether it was a lucky or an unlucky accident." * * * * * The moon laboratory had not been designed for extensive organic chemical analysis. There were only a few things it could do with organic compounds. But these were sufficient to convince Jim that the moon had once been the scene of life. Why so deep? he wondered. Nothing had been found in the upper levels, unless he had missed it--he would have to check that out later. As the drilling head moved slowly downward, the evidence of fossil hydrocarbons increased. There seemed to be an almost geometric increase in concentration after he passed the four-hundred-foot level. He was certain the drill was penetrating a bed of fossil remains of some form of life that flourished the little planet that the moon must have been incalculable eons ago. The more he thought about his theory, however, the more difficult it became to explain all the factors. If the moon had actually been a planet of some far distant system, what had torn it loose from its parent sun and sent it careening through space? Had its sun exploded, blasting whatever planets the system held into the depths of space? Such an occurrence might explain the sterility of the moon's surface, but why was the evidence of life buried so deep? Perhaps the upper layers of the moon's surface consisted of debris blasted from the exploding sun. Such debris would have been molten, flowing about the moon's surface, cremating everything living. Finally, it would have shrunk in the cold depths of space and wrinkled into the vast mountains and cracks that laced the moon's surface. It was one way it could have happened, but it seemed so fantastic that Jim had difficulty in convincing himself that it was true. He doubted the accuracy of his analyses. There were so many tenuous links between the substance on the moon and his own senses that an error in any one of them could destroy the accuracy of the results. But he had no reason to doubt. He began making calibration checks before and after every analysis. It added scores of hours to his work. Sam sat beside him, checking and verifying the accuracy of the telemetering circuits constantly. The operation was as foolproof as their science could make it. "You've got to believe what you find," said Sam. "There's no other answer." And then, one day, Jim found an answer that was utterly impossible to believe. His mind balked and closed up completely at the thought.