For the first time the flicker of a smile brushed across Caldwell’s face.

"Of course we checked with all the bases, Dr. Hunt. Results negative. But that was just the beginning. You see, when they got him back to the labs for a more thorough check, a number of peculiarities began to emerge which the experts couldn’t explain-and, believe me, we’ve had enough brains in on this. Even after we brought him back here, the situation didn’t get any better. In fact, the more we find out, the worse it gets."

"‘Back here’? You mean…

"Oh, yes. Charlie’s been shipped back to Earth. He’s over at the Westwood Biological Institute right now-a few miles from here. We’ll go and have a look at him later on today."

Silence reigned for what seemed like a long time as Hunt and Gray digested the rapid succession of new facts. At last Gray offered:

"Maybe someobody dumped him for some reason?"

"No, Mr. Gray, you can forget anything like that." Caldwell waited a few more seconds. "Let me say that from what little we do know so far, we can state one or two things with certainty. First, Charlie did not come from any of the bases established to date on Luna. Furthermore"-Caldwell’s voice slowed to an ominous rumble-"he did not originate from any nation of the world as we know it today. In fact, it is by no means certain that he originated from this planet at all!"

His eyes traveled from Hunt to Gray, then back again, taking in the incredulous stares that greeted his words. Absolute silence enveloped the room. A suspense almost audible tore at their nerves. Caldwell’s finger stabbed at the keyboard.

The face leaped out at them from the screen in grotesque closeup, skull-like, the skin shriveled and darkened like ancient parchment, and stretched back over the bones to uncover two rows of grinning teeth. Nothing remained of the eyes but a pair of empty pits, staring sightlessly out through dry, leathery lids.

Caldwell’s voice, now a chilling whisper, hissed through the fragile air.

"You see, gentlemen-Charlie died over fifty thousand years ago!"

Dr. Victor Hunt stared absently down at the bird’s-eye view of the outskirts of Houston sliding by below the UNSA jet. The mind-numbing impact of Caldwell’s revelations had by this time abated sufficiently for him to begin putting together in his mind something of a picture of what it all meant.

Of Charlie’s age there could be no doubt. All living organisms take into their bodies known proportions of the radioactive isotopes of carbon and certain other elements. During life, an organism maintains a constant ratio of these isotopes to "normal" ones, but when it dies and intake ceases, the active isotopes are left to decay in a predictable pattern. This mechanism provides, in effect, a highly reliable clock, which begins to run at the moment of death. Analysis of the decay residues enables a reliable figure to be calculated for how long the clock has been running. Many such tests had been performed on Charlie, and all the results agreed within close limits.

Somebody had pointed out that the validity of this method rested on the assumptions that the composition of whatever Charlie ate, and the constituents of whatever atmosphere he breathed, were the same as for modern man on modern Earth. Since Charlie might not be from Earth, this assumption could not be made. It hadn’t taken long, however, for this point to be settled conclusively. Although the functions of most of the devices contained in Charlie’s backpack were still to be established, one assembly had been identified as an ingeniously constructed miniature nuclear power plant. The U235 fuel pellets were easily located and analysis of their decay products yielded a second, independent answer, although a less accurate one: The power unit in Charlie’s backpack had been made some fifty thousand years previously. The further implication of this was that since the first set of test results was thus substantiated, it seemed to follow that in terms of air and food supply, there could have been little abnormal about Charlie’s native environment.

Now, Charlie’s kind, Hunt told himself, must have evolved to their human form somewhere. That this "somewhere" was either Earth or not Earth was fairly obvious, the rules of basic logic admitting no other possibility. He traced back over what he could recall of the conventional account of the evolution of terrestrial life forms and wondered if, despite the generations of painstaking effort and research that had been devoted to the subject, there might after all be more to the story than had up until then been so confidently supposed. Several thousands of millions of years was a long time by anybody’s standards; was it so totally inconceivable that somewhere in all those gulfs of uncertainty, there could be enough room to lose an advanced line of human descent which had flourished and died out long before modern man began his own ascent?

On the other hand, the fact that Charlie was found on the Moon presupposed a civilization sufficiently advanced technically to send him there. Surely, on the way toward developing space flight, they would have evolved a worldwide technological society, and in doing so would have made machines, erected structures, built cities, used metals, and left all the other hallmarks of progress. If such a civilization had once existed on Earth, surely centuries of exploration and excavation couldn’t have avoided stumbling on at least some traces of it. But not one instance of any such discovery had ever been recorded. Although the conclusion rested squarely on negative evidence, Hunt could not, even with his tendency toward open-mindedness, accept that an explanation along these lines was even remotely probable.

The only alternative, then, was that Charlie came from somewhere else. Clearly this could not be the Moon itself: It was too small to have retained an atmosphere anywhere near long enough for life to have started at all, let alone reach an advanced level-and of course, his spacesuit showed he was just as much an alien there as was man.

That only left some other planet. The problem here lay in Charlie’s undoubted human form, which Caldwell had stressed although he hadn’t elected to go into detail. Hunt knew that the process of natural evolution was accepted as occurring through selection, over a long period, from a purely random series of genetic mutations. All the established rules and principles dictated that the appearance of two identical end products from two completely isolated families of evolution, unfolding independently in different corners of the universe, just couldn’t happen. Hence, if Charlie came from somewhere else, a whole branch of accepted scientific theory would come crashing down in ruins. So-Charlie couldn’t possibly have come from Earth. Neither could he possibly have come from anywhere else. Therefore, Charlie couldn’t exist. But he did.

Hunt whistled silently to himself as the full implications of the thing began to dawn on him. There was enough here to keep the whole scientific world arguing for decades.

Inside the Westwood Biological Institute, Caldwell, Lyn Garland, Hunt, and Gray were met by a Professor Christian Danchekker. The Englishmen recognized him, since Caldwell had introduced them earlier by vi-phone. On their way to the laboratory section of the institute, Danchekker briefed them further.

In view of its age, the body was in an excellent state of preservation. This was due to the environment in which it had been found-a germ-free hard vacuum and an abnormally low temperature sustained, even at Lunar noon, by the insulating mass of the surrounding rock. These conditions had prevented any onset of bacterial decay of the soft tissues. No rupture had been found in the spacesuit. So the currently favored theory regarding cause of death was that a failure in the life-support system had resulted in a sudden fall in temperature. The body had undergone deep freezing in a short space of time with a consequent abrupt cessation of metabolic processes; ice crystals, formed from body fluids, had caused widespread laceration of cell membranes. In the course of time most of the lighter substances had sublimed, mainly from the outer layers, to leave behind a blackened, shriveled, natural kind of mummy. The most seriously affected parts were the eyes, which, composed for the most part of fluids, had collapsed completely, leaving just a few flaky remnants in their sockets.