“It’s true. You see the nature of the problem very quickly. Even so, this investigation has to turn into a check of the records, a kind of bookkeepers’ search. As our work so often becomes.” Another ironic smile: “It is not often as dramatic as is sometimes portrayed.”

“That’s fine. But while you’re doing that, what else can we do? What can I do?”

“You can look at the other end of the problem. And I will join you in that.”

“The other end?”

“The motive.”

“But how would you determine that? And having done so, how would you locate it? Doing something like this is so sick that it makes me sick to think about it. It’s evil.”

“Evil!”

“Yes, evil!”

Genette shrugged. “Putting that aside, let us presume anyway that it is rare impulse. And so it may leave signs.”

“That someone hates Terminator? That someone is capable of killing worlds?”

“Yes. It’s not a common impulse. It may therefore stick out. And besides, it may be a political act, a kind of terrorism or war. It may be meant to convey some message, or force some action. So we can follow it that way.”

Swan felt her stomach clenching. “Damn. I mean—there’s never been a, a war in space. We’ve managed without them.”

“Until now.”

That gave her pause. For a generation at least there had been warnings from people all over the system that the conflicts between Earth and Mars could lead to war, or that Earth’s writhing problems were going to drag everyone down with them. Little wars and terrorist attacks and sabotages had never entirely disappeared on poor Earth, and Swan had sometimes thought that diplomats played on the notion that Earth’s discord might spread, in order to boost their own prestige, their own budgets. Diplomacy as necessary peacemaking in a system on the brink—it had been very convenient for them. But what if it turned out to be true?

She said, “I guess I thought spacers knew enough to avoid all that. That once we got out here we would do better. Be better.”

“Don’t be a fool,” the inspector said crisply.

Swan gritted her teeth. After an intense struggle for self-control she said, “But it could be some psychopath. Someone who has lost their mind and is killing just because they can.”

“There are those too,” Genette agreed. “And if one of them got hold of a qube—”

“But anyone can get a qube!”

“Not at all. Not even everyone in space. They are tracked from the factories, and in theory are all located moment to moment. And whichever one was involved would have to be programmed for this, as I said. It would show in its own records what it had done.”

“Aren’t there unaffiliateds that are making qubes?”

“Well—maybe. Probably.”

“So how do we find it, or this person?”

“Or this group?”

“Yes, or nation, or world!”

Genette shrugged. “I want to talk to Wang again, because his qube is really powerful, and he also has the biggest data banks on the unaffiliateds. And also because it’s possible he was attacked by this same entity. But I admit I’m a little afraid to talk to his qube, because we’re seeing so many signs of qubes acting oddly. As if they have volition now, or in any case are being asked to do things unlike anything they’ve done before. Some qubes that we’ve been monitoring are now exchanging messages in an unprecedented way.”

“You mean they’re entangled with each other?”

“No. That seems to be truly impossible, because of decoherence issues. They use radio communication like anyone else, but the messages are encrypted internally at each end, using superposition as they do. So they are truly encrypted, even when we use our own qubes to try and break the codes. This is the reason why I want to keep these discussions out of the earshot of any and all qubes, for the time being. I don’t know which ones to trust.”

Swan nodded. “You’re like Alex in that.”

“That’s right. I used to talk to her about this, and we had the same opinion about this problem. I taught her some procedures to use. So, now I have to think about how to go forward here, and how I can best communicate with Wang and his superqube. Possibly the explanation for all this is even now stored in it, unrecognized because it hasn’t been asked to look for it. Because despite all the talk you hear of balkanization, we are still recording the history of the world down to the level of every person and qube. So to find this agent, we only need to read out the history of the solar system for the last several years, and it should be there.”

“Except for the unaffiliateds,” Swan pointed out.

“Well, yes, but Wang has most of them too.”

“But you don’t want his recording system to know you’re asking,” Swan said. “In case it’s the one doing all this.”

“Exactly.”

Swan never quite stopped feeling sick after that. Someone had meant to kill her city—and yet had missed hitting it directly, thus sparing its citizens, all but the ones who had died in the panic of the evacuation and that poor concert group, killed by the impact.

Was that right? She didn’t know what to make of that—that the impact had missed Terminator itself.

She ended up talking to Pauline about it. She had an idea that she wanted to check, and Pauline was the best way to do it. There she was, after all, her voice in Swan’s ear, and always hearing everything Swan said aloud. There was no way she wasn’t going to find out all about this, eventually.

So: “Pauline, do you know what Inspector Genette and I were talking about when I turned you off?”

“No.”

“Can you guess?”

“You might have been talking about the incident at Ygassdril, which you had just seen. This incident resembles the incident at Terminator in some features. If these were deliberate attacks, then whoever initiated them might have used a quantum computer to help them plot trajectories. If Inspector Jean Genette believed that quantum computers were involved, then the inspector might not want any quantum computers to hear details of the investigation. This would be similar to Alex’s efforts to keep some of her deliberations completely unwitnessed and unrecorded by any AIs, quantum or digital. The assumption seems to be that if quantum computers are in encrypted radio communication with each other, then they may be plotting activities detrimental to people.”

Just as she suspected: Pauline could deduce these things. No doubt many other qubes could too, including Genette’s own Passepartout, programmed in forensics and detection as it certainly must be. If-then, if-then, how many trillion times a second? It might resemble their chess-playing programs, which had proved themselves to be superhumanly good at that particular game. So it was a little bit futile to turn them off only for certain conversations.

Which meant that it was all right for her to say “Pauline, if someone had calculated the trajectory of an impactor to hit Terminator smack on and destroy it, but they forgot to include the relativistic precession of Mercury in their calculation and only used the classical calculus of orbital mechanics, how far would they miss by? Assume the impactor was launched from the asteroid belt a year earlier. Try a few different launch points and trajectory courses and times, both with and without the relativity equations for the precession.”

Pauline said, “The precession of Mercury is 5603.24 arc seconds per Julian century, but the portion of that caused by the curvature of space-time as described by general relativity is 42.98 arc seconds per century. Any trajectory a year in duration, plotted without that factored in, would therefore miss by 13.39 kilometers.”

“Which is about what happened,” Swan said, feeling sick again.

Pauline said, “Being a precession, the miss should have been to the east of the city, not the west.”

“Oh,” Swan said. “Well, then…” She didn’t know what to make of it.