“He did it,” said Noxon.
“Who did what?” asked Wheaton.
“Well, I did it,” said Noxon. “I was watching carefully during the jump through the fold. If we divided, I was going to try to snag the backward-moving ship and bring it back into the forward timeflow.”
“The ship reports that you failed,” said the expendable. “The backward-moving ship in fact moved backward, not making the jump through the fold. But the mice on that ship were able to reprogram the computers to avoid the twenty-fold duplication and then jumped the fold going backward, in order to separate the backward-moving ship from the outbound ship that was us just before our jump.”
“My head hurts,” said Wheaton.
“It does not,” said the expendable. “But your lie is apparently intended to express humorously exaggerated confusion which you do not, in fact, feel.”
“Exactly,” said Wheaton. “It’s nice to have someone get my jokes, even though you have to explain them aloud.”
“I wanted to confirm that I had understood,” said the expendable.
“If they jumped the fold backward,” said Ram, “how are they here?”
“Noxon was able to reverse timeflow and rejoin our spacetime,” said the expendable. “Very good work.”
“Thanks,” said Noxon. “But it wasn’t me.”
“It was you-ish,” said the expendable. “It’s within your capabilities.”
“And then what?” asked Noxon. “He jumped forward to our time?”
“The backward-moving ship had not made the 11,191-year pastward leap that these nineteen ships made. So it arrived in this space in the future, relative to our current timeplace.”
“What did they see there?” asked Ram.
“Not very much,” said the expendable. “The aliens immediately attempted to seize control of the ship’s computers, remotely. The mice were able to resist their reprogramming, which was feeble and unsophisticated compared to the one they will use near Earth several hundred thousand years from now. Then the Noxon of that ship attached to our paths and jumped back to our time, when the aliens are not able to project their computing prowess this far into space.”
“Narrow escape,” said Wheaton.
“It was a very good thing that we had the mice with us,” said Noxon.
“Thank you,” said the alpha mouse. “We’re glad to reward you for refraining from crushing my head.”
“I never wanted to do it,” said Noxon to the mouse.
“Talking to the mice?” asked Wheaton.
“I wonder,” said Ram, “if our presence here, now, accelerated the aliens’ development of the ability to make remote assaults on human computing systems. Having seen us enter their space . . .”
Wheaton agreed. “Why, it might be that our presence is what led them to attack Earth!”
“No,” said Noxon. “They attacked long before we ever showed up here.”
“We’re here now, and that’s hundreds of millennia before the attack,” said Wheaton.
“Prepare for your head to hurt again,” said the expendable.
“Let me guess,” said Wheaton. “‘Before’ doesn’t always mean ‘before.’”
“The calendar and the clock keep a single line of time,” said Noxon. “But with us, causality jumps all over the place. We’re here before the invasion, by the calendar, but we’re here after the invasion, by the causal chain. Their invasion is what caused us to come, so by cause-and-effect, the invasion was first.”
“I can’t even make my little joke,” said Wheaton, “because the expendable already said it.”
“I anticipated your humor?” asked the expendable.
“You stepped on my joke,” said Wheaton. “Clever, but not polite.”
“You’d already said the joke,” said Ram, “so it wasn’t going to be funny this time. Whereas the expendable stepping on it, that was funny.”
“Amusing, anyway,” said the alpha mouse.
“The mice don’t think any of this is all that funny,” Noxon reported.
“Oh, the women are laughing uproariously,” said the alpha. “I’m the one who isn’t hysterical about it.”
Noxon could see that the female mice were busy at various tasks throughout the ship, and not one of them showed any sign of paying much attention to what they were doing.
“What are you doing to the ship?” asked Noxon.
Noxon could see Ram stiffen a little—he must know Noxon was talking to the mice, and so he feared that the mice might be doing something dangerous and irrevocable.
“We’re making the same alterations to this ship that our counterparts made to the backward-moving ship,” said the alpha. “So we can jump the fold without making nineteen forward copies and one backward one.”
“Are we planning to jump again?” asked Noxon.
“I believe that when the expendable finishes explaining about the civilization on the binary planet, you’ll decide that ten of these twenty ships should jump to a spot much nearer the binary.”
“Will they still skip eleven millennia back in time?” asked Noxon.
“No. Curing the replications also cures the time skip.”
“Are you ready for me to explain about the binary planet?” asked the expendable.
“I am,” said Ram. “Unless the mice now command the ship.”
“They’ve fixed it so we don’t split into nineteen pieces every time we jump,” said Noxon.
“You asked them if we’re planning to jump again,” said Ram. “Why would we do that?”
“Let’s hear the expendable and find out,” said Noxon. “The mice apparently already know what he’s going to tell us.”
The expendable took a breath before proceeding. Such theatricality from a machine that doesn’t need to breathe, thought Noxon. “Earth’s Moon was important to the evolution of life, by causing tides and controlling other cycles,” said the expendable. “But this world is really two planets, nearly equal, as close as they can be without tearing each other apart with tidal forces.”
“So both have atmospheres,” said Ram.
“Both have life?” asked Noxon.
“Both have widespread electricity and radio communications,” said the expendable. “They each monitor the other’s radio broadcasts, and I believe the ability to interfere with and eventually control remote computer systems was developed by the nearer planet in order to use it against the farther one.”
“They have a million kilometers between them,” said Ram, “and they’re attacking each other?”
“That suggests reciprocality,” said the expendable. “The nearer planet is attacking the farther one. The farther one seems to be working only to protect their own systems against attack.”
“Let me guess,” said Ram. “The one that attacked us is this aggressive one.”
“I don’t know,” said the expendable. “Whichever world emerges victorious, it will be convinced that the only way to deal with aliens is to destroy them utterly.”
“So even if it’s the nice guys on the far planet,” said Noxon, “they might still be the enemy that attacks Earth.”
The alpha mouse spoke to Noxon. “We don’t know which one is our enemy. Both must be brought under control.”
“It seems wrong to punish one world for what the other world did,” said Noxon.
“We’re not punishing anyone,” said Ram. “We’re saving the human race against a threat, and we don’t know which of these worlds poses that threat.”
“We know that both of them pose a threat,” said the alpha.
“It’s possible that both pose a threat,” said Noxon. “But to take preemptive action against both seems unfair. Stifling a civilization, a species that might be completely innocent—”
“Hold on,” said Wheaton. “Garden has already tried dozens of ways to forestall the destruction of humanity, so there are lots of timestreams in which one of these species wipes out all rivals and rules this bit of the galaxy. The other one was probably destroyed before the victor ever came near us, so we’re not the ones who snuffed them out. All we’re doing now is creating one slim timestream in which the human race survives. It is not so very much to take for ourselves, compared with what they’ve taken already.”