"Perhaps it would be simpler if you explained in person!" MacIntyre snapped, suddenly savage in his confusion.

"But I am explaining in person," the voice said.

"I mean face-to-face," MacIntyre grated.

"Unfortunately, Commander, I do not have a face," the voice said, and MacIntyre could have sworn he heard wry amusement in it. "You see, in a sense, you are sitting inside me."

"Inside—?" MacIntyre whispered.

"Precisely, Commander. I am Dahak, the central command computer of the Imperial ship-of-the-line Dahak."

"Gaaa," MacIntyre said softly.

"I beg your pardon?" Dahak said calmly. "Shall I continue?"

MacIntyre gripped the arms of his chair and closed his eyes, counting slowly to a hundred.

"Sure," he said at last, opening his eyes slowly. "Why don't you do that?"

"Very well. Please observe the visual display, Commander."

Earth vanished, and another image replaced it. It was a sphere, as bronze-bright as the cylinder that had captured his Beagle, but despite the lack of any reference scale, he knew it was far, far larger.

The image turned and grew, and details became visible, swelling rapidly into vast blisters and domes. There were no visible ports, and he saw no sign of any means of propulsion. The hull was completely featureless but for those smoothly rounded protrusions... until its turning motion brought him face-to-face with a tremendous replica of the dragon that had adorned the hatch. It sprawled over one face of the sphere like a vast ensign, arrogant and proud, and he swallowed. It covered a relatively small area of the hull, but if that sphere was what he thought it was, this dragon was about the size of Montana.

"This is Dahak," the voice told him, "Hull Number One-Seven-Two-Two-Nine-One, an Utu-class planetoid of Battle Fleet, built fifty-two thousand Terran years ago in the Anhur System by the Fourth Imperium."

MacIntyre stared at the screen, too entranced to disbelieve. The image of the ship filled it entirely, seeming as if it must fall from the display and crush him, and then it dissolved into a computer-generated schematic of the monster vessel. It was too stupendous for him to register much, and the schematic changed even as he watched, rolling to present him with an exploded polar view of deck after inconceivable deck as the voice continued.

"The Utu-class were designed both for the line of battle and for independent, long-term survey and picket deployment, with core crews of two hundred and fifty thousand. Intended optimum deployment time is twenty-five Terran years, with provision for a sixty percent increase in personnel during that period. Maximum deployment time is virtually unlimited, assuming crew expansion is contained.

"In addition to small, two-seat fighters that may be employed in either attack or defense, Dahak deploys sublight parasite warships massing up to eighty thousand tons. Shipboard weaponry centers around hyper-capable missile batteries backed up by direct-fire energy weapons. Weapon payloads range from chemical warheads through fusion, anti-matter, and gravitonic warheads. Essentially, Commander, this ship could vaporize your planet."

"My God!" MacIntyre whispered. He wanted to disbelieve—God, how he wanted to!—but he couldn't.

"Sublight propulsion," Dahak went on, ignoring the interruption, "relies upon phased gravitonic progression. Your present terminology lacks the referents for an accurate description, but for purposes of visualization, you may consider it a reactionless drive with a maximum attainable velocity of fifty-two-point-four percent that of light. Above that velocity, a vessel of this size would lose phase lock, and be destroyed.

"Unlike previous designs, the Utu-class do not rely upon multi-dimensional drives—what your science fiction writers have dubbed 'hyper drives,' Commander—for faster-than-light travel. Instead, this ship employs the Enchanach Drive. You may envision it as the creation of converging artificially-generated 'black holes,' which force the vessel out of phase with normal space in a series of instantaneous transpositions between coordinates in normal space. Under Enchanach Drive, dwell time in normal space between transpositions is approximately point-seven-five Terran femtoseconds.

"The Enchanach Drive's maximum effective velocity is approximately Cee-six factorial. While this is lower than that of the latest hyper drives, Enchanach Drive vessels have several tactical advantages. Most importantly, they may enter, maneuver in, and leave a supralight state at will, whereas hyper drive vessels may enter and leave supralight only at pre-selected coordinates.

"Power generation for the Utu-class—"

"Stop." MacIntyre's single word halted Dahak's voice instantly, and he rubbed his eyes slowly, wishing he could wake up at home in bed.

"Look," he said finally, "this is all very interesting, uh, Dahak." He felt a bit silly speaking to a machine, even one like this. "But aside from convincing me that this is one mean mother of a ship, it doesn't seem very pertinent. I mean, I'm impressed as hell, but what does anyone need with a ship like this? Thirty-two hundred kilometers in diameter, eighty-thousand-ton parasite warships, two-hundred-thousand-man crews, vaporize planets... . Jesus H. Christ! What is this 'Fourth Imperium'? Who in God's name does it need that kind of firepower against, and what the hell is it doing here?!"

"I will explain, if I may resume my briefing," Dahak said calmly, and MacIntyre snorted, then waved for it to continue. "Thank you, Commander.

"You are correct: technical data may be left to the future. But for you to understand my difficulty—and the reason it is your difficulty, as well—I must summarize some history. Please understand that much of this represents reconstruction and deduction based upon very scant physical evidence.

"Briefly, the Fourth Imperium is a political unit, originating upon the Planet Birhat in the Bia System some seven thousand years prior to Dahak's entry into your solar system. As of that time, the Imperium consisted of some fifteen hundred star systems. It is called the Fourth Imperium because it is the third such interstellar entity to exist within recorded history. The existence of at least one prehistoric imperium, designated the 'First Imperium' by Imperial historians, has been conclusively demonstrated, although archaeological evidence suggests that, in fact, a minimum of nine additional prehistoric imperia intervened between the First and Second Imperium. All, however, were destroyed in part or in whole by the Achuultani."

A formless chill tingled down MacIntyre's spine.

"And just what were the Achuultani?" he asked, trying to keep his strange, shadowy emotions out of his voice.

"Available data are insufficient for conclusive determinations," Dahak replied. "Fragmentary evidence suggests that the Achuultani are a single species, possibly of extra-galactic origin. Even the name is a transliteration of a transliteration from an unattested myth of the Second Imperium. More data may have been amassed during actual incursions, but most such information was lost in the general destruction attendant upon such incursions or during the reconstruction that followed them. What has been retained pertains more directly to tactics and apparent objectives. On the basis of that data, historians of the Fourth Imperium conclude that the first such incursion occurred on the close order of seventy million Terran years ago."

"Seventy mil—?!" MacIntyre chopped himself off. No species could survive over such an incredible period. Then again, the moon couldn't be an alien starship, could it? He nodded jerkily for Dahak to continue.

"Supporting evidence may be found upon your own planet, Commander," the computer said calmly. "The sudden disappearance of terrestrial dinosaurs at the end of your Mesozoic Era coincides with the first known Achuultani incursion. Many Terran scientists have suggested that this may have been the consequence of a massive meteor impact. My own observations suggest that they are correct, and the Achuultani have always favored large kinetic weapons."