There was a fresh spurt of acceleration and a sideways surge of inertia as the vehicle swept through a curved junction and darted into yet another tunnel. It seemed to stretch forever, like the one that had engulfed his Beagle, and his vehicle scooted down its very center. He kept waiting to arrive, but it was a very, very long time before their headlong pace began to slow.

His first warning was the movement of the vehicle’s interior. The entire cockpit swiveled smoothly, until he was facing back the way he’d come, and then the drag of deceleration hit him. It went on and on, and the blurred walls beyond the transparent canopy slowed. He could make out details once more, including the maws of other tunnels, and then they slowed virtually to a walk. They swerved gently down one of those intersecting tunnels, little wider than the vehicle itself, then slid alongside a side opening and stopped. The hatch flicked soundlessly open.

“If you will debark, Commander?” the mellow voice invited, and MacIntyre shrugged and stepped down onto what looked for all the world like shag carpeting. The vehicle closed its hatch behind him and slid silently backwards, vanishing the way it had come.

“Follow the guide, please, Commander.”

He looked about blankly for a moment, then saw a flashing light globe hanging in mid-air. It bobbed twice, as if to attract his attention, then headed down a side corridor at a comfortable pace.

A ten-minute walk took him past numerous closed doors, each labeled in a strangely attractive, utterly meaningless flowing script, and air as fresh and cool as the docking cavern’s blew into his face. There were tiny sounds in the background, so soft and unintrusive it took him several minutes to notice them, and they were not the mechanical ones he might have expected. Instead, he heard small, soft stirrings, like wind in leaves or the distant calls of birds, forming a soothing backdrop that helped one forget the artificiality of the environment.

But then the corridor ended abruptly at a hatch of that same bronze-colored alloy. It was bank—vault huge, and it bore the first ornamentation he’d seen. A stupendous, three-headed beast writhed across it, with arched wings poised to launch it into flight. Its trio of upthrust heads faced in different directions, as if to watch all approaches at once, and cat-like forefeet were raised before it, claws half-extended as if to simultaneously proffer and protect the spired-glory starburst floating just above them.

MacIntyre recognized it instantly, though the enormous bas—relief dragon was neither Eastern nor Western in interpretation, and he paused to rub his chin, wondering what a creature of Earthly mythology was doing in an extra-terrestrial base hidden on Earth’s moon. But that question was a strangely distant thing, surpassed by a greater wonder that was almost awe as the huge, stunningly life-like eyes seemed to measure him with a calm, dispassionate majesty that might yet become terrible wrath if he transgressed.

He never knew precisely how long he stood staring at the dragon and stared at by it, but in the end, his light-globe guide gave a rather impatient twitch and drifted closer to the hatch. MacIntyre shook himself and followed with a wry half-smile, and the bronze portal slid open as he approached. It was at least fifteen centimeters thick, yet it was but the first of a dozen equally thick hatches, forming a close-spaced, immensely strong barrier, and he felt small and fragile as he followed the globe down the silently opening passage. The multi-ply panels licked shut behind him, equally silently, and he tried to suppress a feeling of imprisonment. But then his destination appeared before him at last and he stopped, all other considerations forgotten.

The spherical chamber was larger than the old war room under Cheyenne Mountain, larger even than main mission control at Shepherd, and the stark perfection of its form, the featureless sweep of its colossal walls, pressed down upon him as if to impress his tininess upon him. He stood on a platform thrust out from one curving wall—a transparent platform, dotted with a score of comfortable, couch—like chairs before what could only be control consoles, though there seemed to be remarkably few read-outs and in-puts—and the far side of the chamber was dominated by a tremendous view screen. The blue-white globe of Earth floated in its center, and the cloud—swirled loveliness caught at MacIntyre’s throat. He was back in his first shuttle cockpit, seeing that azure and argent beauty for the first time, as if the mind-battering incidents of the past hour had made him freshly aware of his bond with all that planet was and meant.

“Please be seated, Commander.” The soft, mellow voice broke into his thoughts almost gently, yet it seemed to fill the vast space. “Here.” The light globe danced briefly above one padded chair—the one with the largest console, at the very lip of the unrailed platform—and he approached it gingerly. He had never suffered from agoraphobia or vertigo, but it was a long, long way down, and the platform was so transparent he seemed to be striding on air itself as he crossed it.

His “guide” disappeared as he settled into the chair, not even blinking this time as it conformed to his body, and the voice spoke again.

“Now, Commander, I shall try to explain what is happening.”

“You can start,” MacIntyre interrupted, determined to be more than a passive listener, “by explaining how you people managed to build a base this size on our moon without us noticing.”

“We built no base, Commander.”

MacIntyre’s green eyes narrowed in irritation.

“Well somebody sure as hell did,” he growled.

“You are suffering under a misapprehension, Commander. This is not a base ’on’ your moon. It is your moon.”

For just an instant, MacIntyre was certain he’d misunderstood.

“What did you say?” he asked finally.

“I said this is your moon, Commander. In point of fact, you are seated on the command bridge of a spacecraft.”

“A spacecraft? As big as the moon?” MacIntyre said faintly.

“Correct. A vessel some three thousand-three-two-oh-two-point-seven-nine-five, to be precise—of your kilometers in diameter.”

“But—” MacIntyre’s voice died in shock. He’d known the installation was huge, but no one could replace the moon without someone noticing, however advanced their technology!

“I don’t believe it,” he said flatly.

“Nonetheless, it is true.”

“It’s not possible,” MacIntyre said stubbornly. “If this thing is the size you say, what happened to the real moon?”

“It was destroyed,” his informant said calmly. “With the exception of sufficient of its original material to make up the negligible difference in diameter, it was dropped into your sun. It is standard Fleet procedure to camouflage picket units or any capital ship that may be required to spend extended periods in systems not claimed by the Imperium.”

“You camouflaged your ship as our moon? That’s insane!”

“On the contrary, Commander. A planetoid—class starship is not an easy object to hide. Replacing an existing moon of appropriate size is by far the simplest means of concealment, particularly when, as in this case, the original surface contours are faithfully recreated as part of the procedure.”

“Preposterous! Somebody on Earth would have noticed something going on!”

“No, Commander, they would not. In point of fact, your species was not on Earth to observe it.”

“What?!”

“The events I have just described took place approximately fifty-one thousand of your years ago,” his informant said gently.

MacIntyre sagged around his bones. He was mad, he thought calmly. That was certainly the most reasonable explanation.