Pirius felt that deep anger welling again. “Millions of human lives were lost in the defeat of ships like this. And you’ve built a, a monument to our enemy.”

“Yes,” she said testily. “As you’ve said before. But don’t you think we need to understand what it was we killed?”

He thought he didn’t understand her at all. “Is that why you’re here? Were you always so curious about Ghosts?”

She hesitated, perhaps wary of giving away too much of herself. “I suppose so — yes. I’ve always been a Commissary. I started in the Office of Doctrinal Responsibility: very dry work! I was always blighted by curiosity. Not a good characteristic in the Commission for Historical Truth.” Her smile, behind her visor, was thin. “Then I found out about this facility, and a number of others, where life- forms generally supposed lost during the Assimilation have been preserved — or, as in the case of the Ghosts, revived.”

“There are others?… Never mind. How did you find out?”

She smiled again. “The control of the Commission isn’t as complete as some like to imagine. Truth finds a way. So I volunteered to come here. The powers that be were surprised, but they processed my application. Pluto is generally a punishment detail, you know. You come here to make amends, to end your career — certainly not to progress it.”

“And was it worth it?”

“Oh, yes, Ensign. It was worth it.” She led him around the periphery of the mocked-up cruiser. “I mean, look at this. What’s fascinating about the Ghosts to me isn’t their technological capabilities but their story: their origin, their account of themselves. You know, the Ghosts call the sky the Heat Sink — the place the heat went.” Since their world had frozen, Mara said, the Ghosts had not been shaped by competitive evolution, as humans had, but by cooperation. “They are symbiotic creatures. They derive from life-forms that huddled into cooperative collectives as their world turned cold. Every aspect of their physical design is about conserving heat, precious heat.

“And they seem to be motivated not by expansion for its own sake, as we are, but by a desire to understand the fine-tuning of the universe. Why are we here? You see, Ensign Pirius, there is only a narrow range of physical possibilities within which life of any sort is possible. We think the Ghosts were studying this question by pushing at the boundaries — by tinkering with the laws which govern us all.”

“But that made them dangerous.”

“Yes,” Mara said. “An enemy who can use the laws of physics as a weapon is formidable. But they developed their capabilities, not as some vast weapons program, but for their own species imperative. Until they ran up against humans, it had nothing to do with us…”

Pirius sensed movement behind him. A Silver Ghost hovered massively, a few meters away, just above the ice surface.

Mara said quickly, “It’s only the Sink Ambassador. It must have followed us. It’s probably curious.”

“Curious? You talk as if it’s a child.” Pirius saw himself reflected in the Ghost’s complacent hide. “You,” he said. “You are the Sink Ambassador?”

“That is what I am called.”

“Is she right? That you Ghosts follow your own logic, that you care nothing for humans?”

“I don’t know,” the Ghost said. “I have no reliable data on the past.”

Mara said dryly, “These new Ghosts won’t believe a word we say about their history. Maybe they’re right not to.”

“We destroyed you,” Pirius said. “And we brought you back. Everything about you is in our power.”

“True. But that doesn’t alter my perception of you.”

Fists clenched, Pirius stepped up to the Ghost. Suddenly all the complex emotions he had been feeling — his inbred hatred of the Ghosts, his confusion at the reaction of Mara and the others, all that had struck him so overwhelmingly since the day his own future self had docked at Arches — welled up in him. And here was a Silver Ghost, right in front of him. He said on impulse, “Perhaps Mara is right. Perhaps I must learn about you, as you have learned about humans.”

Mara was disturbed. “What are you doing, Ensign?”

“Remove your hide. Disassemble yourself. Show me what you are.”

Mara laid a gloved hand on Pirius’s arm. Her eyes were bright with anger. “I knew I shouldn’t have brought you here.”

Pirius shook her off. “I command this Ghost. I am human.”

The Ghost was motionless, save for its usual subtle wafting, and Pirius, shaking with anger, wondered what he would do if the Ghost refused. He remembered his training on how to fight a Ghost. That hide was tough, but if you used all your strength you could get your knife into it, and then you could use the Ghost’s own rotation against it and open it up…

The Ghost’s hide puckered, and shallow seams formed, stretching from one pole of the glistening sphere to another, segmenting the surface. The Ghost quivered briefly — then one seam split open. A sheet of crimson fluid gushed out, strikingly like human blood. It had frozen into crystals long before it fell to the Pluto ice.

A Virtual of Nilis coalesced with a snap. “Stop this.” He stood between Pirius and the Ghost. “You, Ambassador. Heal yourself.”

The gash in the Ghost’s hide closed, leaving only a pale scar. A stark slick of frozen blood showed how much it had lost in those brief moments.

Nilis turned on Pirius. He thundered, “What were you thinking, Ensign? To deal with this I have been forced to leave a meeting I crossed Sol system to attend! Is this really your highest aspiration — the highest achievement of mankind, after twenty thousand long years of interstellar conquest — to use your petty power to cause another sentient creature to destroy itself? Why?”

Because it’s what I’m trained to do, Pirius thought helplessly. But he flinched from Nilis’s furious glare.

“Who is it you’re angry at, Ensign?” Mara asked. “The Ghost? Or is the Ghost just a target? Perhaps you are angry at the lies that you have been told throughout your life. Now you have been brought to Sol system you see the truth, and you can’t handle your rage. But you don’t know who to blame.”

“Shut up,” Pirius said.

“Perhaps you would rather have died in combat, without having to deal with such complex truths—”

“Shut up!”

Unexpectedly the Ghost spoke. Its translated words were as toneless as ever. “I gladly obeyed the ensign’s command. I am not afraid to die.”

Nilis turned and inspected the Ghost. “Is that really true?” In an instant, Pirius saw resentfully, he had forgotten Pirius, and was taken over once more by his own endless curiosity. “But what consolation can there be for death? Tell me, Ghost — do you have gods?”

Mara warned, “All it knows of its culture is what we have taught it. As if the Ghosts studied a human religion, filtered it through their own preconceptions and gave it back to us.”

“Yes, yes,” Nilis said impatiently. “I understand that. Nevertheless—”

The Ghost said, “Not gods of the past.”

“No,” said Nilis rapidly. “Of course not. Human gods were creators. But your world betrayed you, didn’t it? What creator god would do that?”

“The past is a betrayal. The future is a promise.”

Mara said, “Commissary, we have tried to study Ghost philosophy. The Ghosts have a different perception of the universe than us, a different story about themselves to tell. Nobody’s really sure if concepts like religion actually map across to such alien minds.”

“Oh, of course,” Nilis said. “But I’m of the school that holds that something like religious concepts must arise in any sentient form. Perhaps all mortal creatures, humans or Ghosts, must develop a philosophy to cushion the shock of imminent personal death.”

Mara nodded. “I’d certainly concede that religious beliefs have survival value — and are likely to play an evolutionary purpose.”