Willing his fists to relax, Thssthfok set down the helmet and finished removing his armor. The opportunity to resist would come.

SIGMUND TWITCHED AS THE PRISONER removed his helmet. Those eyes! They were so human human. But by human standards the head was grotesque: misshapen, topped by a bony crest, totally hairless, and too large for its body. The skin looked leathery. The face had neither lips nor gums, only a hard, nearly flat, toothless beak.

Sigmund watched a holo, not the prisoner himself. Only a few fiber-optic cables penetrated into the improvised cell. There had scarcely been time, before the improvised restraint-field generator drained its battery, to empty the auxiliary cargo hold and run cables for monitoring. No active bugs, whose electronics might somehow be co-opted.

"Are you all right, Sigmund?" Kirsten asked. She shared the corridor with him, standing on the other side of the holo. The rest of the crew watched from their posts. "You look upset."

Sigmund shivered, in the grip of deja vu. He hoped his suspicions were misplaced. "I'm not sure."

Within his cell the prisoner began stripping off battle gear. Inside the pressure suit he had looked humanoid, but that was only a matter of overall shape. Briskly now, having taken to heart the gravity-field lesson, he worked his way out of the suit.

His chest, like his face, was flat and leathery. The more of that body emerged, the more clearly humanoid he was. He had joints where a human had them-only the prisoner's joints were grossly enlarged. His elbows were as large as softb.a.l.l.s. His hands were k.n.o.bby, his fingers like strings of walnuts. The fingers lacked nails but the tips suggested retractable talons.

Not he. Not she, either. It. The prisoner's crotch lacked s.e.x organs.

Sigmund's hands trembled. He willed them to stop.

"What's happening?" Baedeker demanded over the intercom. From the safety of his locked cabin, no doubt.

Only Sigmund did not believe any of them was safe. He managed not not to order Jeeves to open the cargo-hold hatch and vent the air. He needed to know what the prisoner could tell them. to order Jeeves to open the cargo-hold hatch and vent the air. He needed to know what the prisoner could tell them.

Sigmund had once seen such a creature, or at least its mummified remains. In an earlier life. In Washington, at the Smithsonian Inst.i.tute, of all places.

He took a deep breath. "I know who our enemies are. It is not not good." good."

25.

"The intruder entered Sol system in 2125," Sigmund said, although Earth's calendar had meaning only to Jeeves and himself. "More than half a millennium ago."

To be precise, a good 550 Earth years earlier. Only any claim to precision was laughable, given the gaping holes in Sigmund's and the AI's memories. By Sigmund's best approximation, the present Earth date was 2675.

From their customary seats around the relax-room table, Kirsten, Eric, and Baedeker waited for Sigmund to continue. Jeeves listened in while keeping watch on the prisoner, no longer pretending that he was on the bridge.

The Gw'oth partic.i.p.ated from their habitat. By choice, Sigmund wondered guiltily, or because the path was blocked? Without Er' o's help, Sigmund would never have captured the prisoner-and Sigmund had welded the Gw'oth into the cargo hold.

Did they know that they were trapped? He should know, but didn't. With equal delicacy, no one ever mentioned hiding sensors in the cargo hold, or finding and neutralizing them. It was a game of cat and mouse like Sigmund had played with Puppeteer agents back on New Terra. Aboard they know that they were trapped? He should know, but didn't. With equal delicacy, no one ever mentioned hiding sensors in the cargo hold, or finding and neutralizing them. It was a game of cat and mouse like Sigmund had played with Puppeteer agents back on New Terra. Aboard Don Quixote Don Quixote, the mice-that was to say, the Gw'oth-appeared to hold the advantage.

Sigmund clutched a drink bulb, more to steady his hands than from any interest in the coffee. So: 2125. Only the saga began long before that.

He started over. "Humans aren't native to New Terra. You've always always known that. Well, it turns out humans aren't native to Earth, either." known that. Well, it turns out humans aren't native to Earth, either."

"What?" Kirsten and Eric shouted, nearly in unison. Baedeker's comment, orchestral and discordant, sounded equally surprised.

"The year 2125. That's when a few learned otherwise." Sigmund's mind's eye offered up the mummified alien he had once seen. Far away. Long ago. "Jeeves, what records do you have on the incident?"

"Very little, Sigmund, a.s.suming I'm correct to what incident you refer." A hologram formed over the relax-room table, a museum display of a s.p.a.cesuit with great ball joints at the knees and elbows. The gear closely matched the suit worn by their captive.

Jeeves went on. "As you say, in 2125 an alien ship appeared from deep s.p.a.ce. A ramscoop. Belter and United Nations authorities found one alien aboard: the pilot, long dead. His equipment was eventually donated to the Smithsonian. The body carried a pathogen-it killed some of those who intercepted the ship-and was destroyed. The authorities kept the derelict itself for study."

"Thank you, Jeeves," Sigmund said.

That, until well after Long Pa.s.s Long Pa.s.s and Jeeves departed Earth, had been the entire story for public consumption. There had been no choice but to tell the public something. The alien ship used magnetic monopoles; its approach had triggered monopole detectors across Sol system. and Jeeves departed Earth, had been the entire story for public consumption. There had been no choice but to tell the public something. The alien ship used magnetic monopoles; its approach had triggered monopole detectors across Sol system.

After centuries pa.s.sed without similar visitors, the authorities had relaxed a bit. They admitted they had quarantined the alien corpse, not incinerated it. The Smithsonian exhibit now included the dead pilot's body.

Even in Sigmund's day, that was all Sol system's public knew, but he wasn't from the clueless majority. He had been in the Amalgamated Regional Militia, the UN's una.s.sumingly named police/military/intelligence organization. Kirsten and Eric knew that bit about Sigmund's past-and that he was loath to discuss his former life. He had told even Penny little more than that. It dredged up too many painful memories.

He had to discuss it now.

Sigmund hadn't been just any ARM, but a high-ranking member of the Bureau of Alien Affairs. That was how he wound up spending so much of his time stalking Puppeteers. That was why Nessus had stalked him him.

And Alien Affairs had had extensive files, still heavily cla.s.sified, about the 2125 incident.

Sigmund remembered checking out the archives when his clearance finally allowed him to. Interesting stuff, but-so it had seemed-ancient history. Very Very ancient. ancient.

He wished now he had studied them more thoroughly.

Sigmund said, "About three million years ago, a generation ship left a planet somewhere near the galactic core. That vessel traveled deep into one of the spiral arms before the crew, from a species calling itself the Pak, found a world to colonize. Only their colony failed."

He brought up a second holo, of the improvised cell in which their prisoner moved ceaselessly. The match between their captive and the museum's s.p.a.cesuit was undeniable.

A pacing human tends to retrace his steps, but the prisoner slightly altered its route with every circuit. Each lap would offer a slightly different perspective on its cell, the opportunity to glimpse something overlooked on previous perambulations.

So what, in their haste to empty the room, had Sigmund and Eric carelessly left behind? (Baedeker had been too terrified to help. Kirsten, her arm just put back into its socket, had been unable to help. After hours in the autodoc she looked much better.) If anything at all had been overlooked, this prisoner would find it. And use it against them.

"And Earth has records of ancient Pak," Kirsten said dubiously.

Paleontology was surely obscure to her, if she could even articulate the concept. All life on New Terra had a recent and well-doc.u.mented beginning. Whether of Hearth or Earth origin, everything everything had been transplanted by Puppeteers. The primitive life that had gone before, source of the oxygen-rich atmosphere that had made the world ripe for exploitation, had perished in the interstellar deep freeze while Puppeteers moved the future Nature Preserve Four to their Fleet. had been transplanted by Puppeteers. The primitive life that had gone before, source of the oxygen-rich atmosphere that had made the world ripe for exploitation, had perished in the interstellar deep freeze while Puppeteers moved the future Nature Preserve Four to their Fleet.

Puppeteers not only lacked curiosity, they discouraged it. They cared nothing about the primordial ecosystem they had obliterated, nor did they allow their servants to waste time on anything as useless as the dead past. New Terran scientists were as curious as anyone Sigmund had ever met. Still, since independence, concerns far more urgent than ocean-floor microfossils from pre-NP4 days had occupied them. Like keeping the present ecology healthy, despite the disappearance of tides....

Yearning for Penelope-her smile, her grace, her touch, everything-burst out of Sigmund. Burst over Sigmund. They had been apart so so long. long.

He struggled to set aside the hunger, to focus. For Penny more than anyone.

Fossils. Ecology. Pak. Something nagged at Sigmund. "Nature, red in tooth and claw," he muttered.

Kirsten eyed him strangely. Baedeker shuddered.

Where was that phrase from? Sigmund couldn't remember, whether from Nessus' meddling or the pa.s.sage of time.

"Tennyson," Jeeves said. "From-"

The poem hardly mattered. Sigmund, finally, had grasped the deeper issue.

Even the brightest New Terran scientists failed to get evolution. Oh, they understood it intellectually, but they did not feel feel it. Not at a visceral level. How could they? Their biosphere was simply too young. Except on the tiniest of scales, in slight variations of crops and insect populations, they had yet to see natural selection in action. it. Not at a visceral level. How could they? Their biosphere was simply too young. Except on the tiniest of scales, in slight variations of crops and insect populations, they had yet to see natural selection in action.

They could not understand the terrible evolutionary imperatives that drove the Pak.

So to Kirsten's implied question. Yes, Earth had skeletal remains. They had been short, the adults typically about five feet in height. They had disproportionately long arms and receding foreheads. With a brain capacity at best half that of modern humans, the creatures could have been at best marginally sapient. Paleontologists called them h.o.m.o habilis, and over a couple million years they had evolved into h.o.m.o sapiens.

And no, because Earth failed to nurture a plant on which the colonists had depended. Pak like their prisoner-with its backward-bulging cranium, and Finagle alone knew how smart it was-had been rare in the colony. Nothing like it had been found in the fossil record.

All that detail could wait. Sigmund answered Kirsten with a nod. "The colony transmitted a distress call. Long after, a starship responded, loaded with supplies. A one-person ship whose pilot looked"-Sigmund gestured at their prisoner-"just like him."

"The ship reaching Sol system in your year 2125," Baedeker prompted. "And yet no one knows."

Sigmund nodded again. "Luckily for us all, a Belter prospector named Jack Brennan, a singleship pilot, was first to reach the incoming ramscoop. Everything we know"-or believe we know-"about the Pak, we learned from Brennan.

"Contrary to what the public was told, the ramscoop pilot was very much alive. He took Brennan captive." The Pak's name was almost all consonants. Phssthpok, Sigmund recalled, or something similar. A transliteration, obviously. Probably it took a beak and hardened palate to enunciate correctly. "Aboard the Pak ship, Brennan got a whiff of an alien vegetable.

"To a Pak or human of suitable age, the smell of tree-of-life root is irresistible. Brennan gorged on the tubers. The symbiotic virus in the roots turned him into"-Sigmund gestured at the holo-"something like that. Because that that is meant to be a human's final life stage." is meant to be a human's final life stage."

Eric froze the holo, rotating it slowly, examining their prisoner from every side. "Those huge joints. They're like the world's worst case of arthritis, gone untreated. The toughened, wrinkled skin. The lack of teeth and hair. It's almost like old age."

"Exactly." Sigmund sipped from his drink bulb, gathering his thoughts. "What we know as old age is the body's abortive attempt to transform. Changing successfully takes the retrovirus insinuated into the host's genetic code. Then you get skin like armor, increased muscle ma.s.s and the enlarged bones and joints to handle it, and other modifications. At the top of the list is a greatly enlarged brain.

"That ancient colony failed because tree-of-life didn't grow properly on Earth. The plant grew, but it didn't support the symbiotic virus. Without the virus, the adult colonists never reached the third stage of life, which is"-again, Sigmund pointed at the holo-"that. The cargo Brennan found was mostly tree-of-life seeds and trace elements critical to proper tree-of-life growth. If Brennan was correct, that final stage can live for fifteen hundred years."

Only few Pak did, and therein was the problem. Evolutionary pressures, tanj it! Sigmund wondered if he could make his crew understand. Make them believe.

"And Brennan became ... like that," Eric repeated skeptically.

"That's the point," Sigmund said. That Brennan could could transform was compelling evidence, if you understood evolution, of the close kinship between humans and Pak. Still, just as h.o.m.o sapiens varied from its h.o.m.o habilis ancestors-a brain twice as large, for starters-the respective nextstage forms had their differences. "Then they talked. Brennan said the Pak was far smarter than any human." transform was compelling evidence, if you understood evolution, of the close kinship between humans and Pak. Still, just as h.o.m.o sapiens varied from its h.o.m.o habilis ancestors-a brain twice as large, for starters-the respective nextstage forms had their differences. "Then they talked. Brennan said the Pak was far smarter than any human."

Transformed, Brennan himself had become smarter still.

Sigmund kept that that detail to himself. It hinted at a way to outthink the enemy, but with a terrible sacrifice. Wherever a Pak lived, tree-of-life root must be available nearby. Certainly on the world of the flying squirrels. Perhaps even a few tubers, emergency rations, inside the sealed box of the prisoner's gear. detail to himself. It hinted at a way to outthink the enemy, but with a terrible sacrifice. Wherever a Pak lived, tree-of-life root must be available nearby. Certainly on the world of the flying squirrels. Perhaps even a few tubers, emergency rations, inside the sealed box of the prisoner's gear.

The ARM might have kept Phssthpok's cargo as insurance against future emergencies. They chose, instead, to destroy it. Things did not look quite quite so desperate that Sigmund wanted to plant in the mind of anyone here the possibility of exposing themselves to tree-of-life. so desperate that Sigmund wanted to plant in the mind of anyone here the possibility of exposing themselves to tree-of-life.

Eric had a guarded expression on his face. Did he suspect?

Best to change the subject. Sigmund took a deep breath. "When Brennan got the chance, he killed the Pak."

Baedeker pawed spasmodically at the deck. "This Pak crossed much of the galaxy to help your people, to extend their lives, to enhance their minds, and the first human it met killed it?"

Yes, because that was the right thing to do! The only only thing! thing!

Brennan had explained his actions all those years ago to ARM and Belter authorities-before escaping with contemptuous ease from their custody and disappearing from history. Sigmund summarized Brennan's argument. "The final life stage is called protector. Protecting their bloodline: That's what they're about. That's all all they're about. They themselves are sterile. they're about. They themselves are sterile.

"Protectors battle instinctively, incessantly, single-mindedly, for their families. They exterminate rival clans without qualm or hesitation. That That is what would have become of Earth had Phssthpok survived. And such will be the fate of any human world on which tree-of-life ever gets loose." is what would have become of Earth had Phssthpok survived. And such will be the fate of any human world on which tree-of-life ever gets loose."

Yet Brennan had abandoned his children. Belter authorities told Brennan's family only that contagion from food in the alien ship had taken him-truth of a sort-and that for safety the body had been incinerated into atoms. Maybe Brennan's above-Pak intelligence let him resist his protector instincts. Or-a flash of weird insight-maybe Brennan disappeared for for his children. his children.

Could Brennan's absence have helped his family? If not his absence, then something he intended to- Baedeker erupted into noise: a frenzied and arrhythmic bleating, jarringly atonal. Sigmund's concentration faltered. The rickety structure of inference and conjecture collapsed.

With a shudder, Baedeker regained control of himself. His flanks trembled. His heads twitched, stealing peeks at the exit.

"Unending conflict among the Pak clans," Kirsten said wonderingly. "That's why eons pa.s.sed between the colony ship and the rescue attempt. Resources gathered to prepare for such an epic journey would tempt every other clan. It's probably why, in millions of years, the Pak have not advanced beyond fusion-powered ships. That's the first good news we've had."

Good news? No, Sigmund thought sadly, she doesn't get it. Millions of years in ceaseless warfare, clan against clan. Millions of years of natural selection: for tactical brilliance, combat prowess, and utter ruthlessness. Millions of years evolving into the galaxy's consummate warriors.

That was who, in hundreds upon hundreds of ships, killing every civilization in sight, was rushing down New Terra's throat... . was who, in hundreds upon hundreds of ships, killing every civilization in sight, was rushing down New Terra's throat... .

What good could come of burdening everyone with Sigmund's own sense of doom? It was time, yet again, to change the subject. "That's enough for now. I need to talk to the prisoner."

26.

Thssthfok strode about his cell, his eyes in constant motion.

His only value to his captors was the information he might give them-and he was determined to give them nothing useful. He could serve the Pak by escaping. Or by dying.

That he continued to study the cell was misdirection, for surely his captors watched through hidden sensors. He had long ago completed an inventory of useful materials. For sophisticated parts, the repair kit he had palmed from a pocket of his armor. To fashion into structural elements, bolts and brackets from the empty shelving units, and parts from the latching mechanisms within the empty cabinets. From the corners and recesses of the room, sc.r.a.ps in endless variety, all individually innocuous, the sign of a room hastily emptied. To run what he would build, the magnetically coupled wireless power transmitters recessed into the walls. And for the privacy in which to construct-whatever-the empty storage units themselves, their interiors invisible to watchers.

Like the briefly glimpsed air lock, every mechanism in this prison was straightforward in function, designed for a single obvious purpose, and profligate in its use of materials. His captors, like the Drar, must be a young race, their worlds all but unexploited. He could fashion many things from the components at his disposal, and what he would make-multipurpose, tiny, frugal in its use of resources-might go unnoticed among such primitives.

The situation was clear. He would escape and take charge of the ship. He would, if possible, take prisoners for the information they might provide. If their capture proved impractical, the ship itself would reveal much- An eruption of noise: complexly modulated, unintelligible, not altogether unpleasant. Speech. It came from a tiny grille high on an interior wall, and Thssthfok added an audio transducer of unknown type to his list of building materials.

He saw flashes, roughly synchronized to the sounds, at the entrance into his cell. From the rectangular display device still attached to the inset window of the hatch. An image of his battle armor and a sound burst. An image of his captor's s.p.a.ceship and another sound burst. An image of Thssthfok himself-and silence.

"Thssthfok," he offered.

And so the language lessons began.

IN THE PRIVACY OF HIS CABIN and inadequate comfort of his own rolledup body, Baedeker trembled. The wonder was that he had made it to his cabin before collapsing. Sigmund's revelations had left him teetering on the brink of catatonia.

Pak fought other clans to extinction! Valuing their own kind so little, of course Pak attacked any other possible threat without hesitation. And so they had, with all those kinetic-kill genocides. And Hearth was in their path.