“This time it will be different,” Mikhail said. “The ground will be directly engaged.”

Bud snapped, “What does that mean? Stick to English, damn it.”

Eugene replied, “These solar particles are so energetic that most of them will cut through the magnetosphere, and atmosphere, as if they aren’t there—”

“Like bullets through paper,” Mikhail said.

A lethal hail of radiation and heavy particles would slam onto land and sea. For an unshielded human, it would be like a trillion tiny explosions going off inside her cells; her delicate biomolecules, the proteins that built her and the genetic material that governed her structure and growth, would be smashed apart. Many people would die immediately. For those who lived, the suffering was only postponed. Even unborn children would suffer mutations that could kill them on their emergence from the womb.

Every living thing on Earth, every one of them reliant on proteins and DNA, would be similarly affected. Even where individuals survived, ecologies everywhere would be devastated.

Eugene kept talking, pitilessly, about long-term problems. “After the cloud has passed the air will be full of carbon-14, because of neutron capture by nitrogen nuclei. Very radioactive. And even when the farms start working again all that stuff is bound to get into the food chain. Ocean stocks would be least affected, until the die-off in the seas cuts in …”

Bud got the message. The disaster would continue to unfold, as far ahead as could be seen. Shit, he thought. And it was going to start in an hour, just an hour.

Impulsively Bud tapped his softscreen, and flicked at random through images of Earth.

Here were the last forests of South America, so doggedly preserved, and the soybean fields that had crowded them out, burning together. Here were the almost clichйd landmarks of the human world collapsing in flames: the Taj Mahal, the Eiffel Tower, the Sydney Harbor Bridge. Here were great ports laid waste by the monstrous storms, spaceplanes crushed like moths, the bridges of Japan and Gibraltar and across the English Channel left smashed and twisted by massive lightning strikes. Even so, everybody thought the worst was over; everywhere people toiled in the rubble of their homes seeking survivors, sifting debris, already trying to make a new start. And now, this. And what about the shield? With no protection at all, surely it would be destroyed, a leaf in a gale.

After all they had been through it seemed unfair, as if some grown-up was changing the rules of the game, just when they had been about to win. But maybe, Bud thought uneasily, if that nutty soldier from Britain was right about her “Firstborn,” that was exactly what had happened.

Suddenly he longed to be with Siobhan. If she were here with him it wouldn’t seem so bad, he thought. But that was a selfish thing to wish for; on Earth, wherever she was, she was safer than she would be up here.

He faced the softscreens, Mikhail’s grave face. He was aware of his people watching him; even now he had to think about morale. “So,” he said. “What options do we have?”

Mikhail only shook his head. Eugene, his eyes flickering nervously, looked away.

Unexpectedly, Athena spoke up. “I have one.”

Bud looked up, bemused. On the softscreen, Mikhail’s jaw had dropped.

“Don’t worry, Bud. I felt just as bad about this when I first figured it out. But we’ll get through this, you’ll see.”

Bud snapped, “What are you talking about, Athena? How will we get through this?”

“I’ve already taken the liberty of warning the authorities,” Athena said evenly. “I have made contact with the offices of the Presidents of Eurasia and America, and the leadership units in China. I began this process when the sunstorm was still under way. Bud, I didn’t want to disturb you. You were rather busy.”

Bud said, “Athena—”

“Just a minute,” Mikhail said. “Athena, let me get this straight. You sent your warning messages before we came online. So you figured all this out before Eugene and I reported our observations of the mass ejection to Colonel Tooke.”

“Oh, yes,” Athena said brightly. “I didn’t make my warnings on the basis of your observations. They just confirmed my theoretical predictions.”

Eugene said, “What theoretical predictions?”

Bud growled, “Mikhail, tell me what’s going on here.”

“She seems to have figured out the particle storm,” Mikhail said, wondering. “Athena evidently ran her own models—and they were better than ours—and she saw the particle storm coming, where we couldn’t. That was how she was able to make her warnings to the authorities even while we were still struggling with the sunstorm itself.”

“I am rather bright, you know,” Athena said without a trace of irony. “Remember that I am the most densely interconnected and processor-rich entity in the solar system. The failure of Eugene’s model, pushed to its extremes, was quite predictable. Not that any blame accrues. You did your best.”

Eugene bridled visibly.

“But my modeling—”

Bud said, “Athena. No bullshit. How long before us did you figure this out?”

“Oh, I’ve known since January.”

Bud thought back. “Which was when you were switched on.”

“I didn’t work it out immediately. It took me a while to process the data you had stored in me, and to come to a conclusion. But the implications were clear.”

“How long did it take?—No, don’t answer that.” For an entity as smart as Athena it was quite possible that the answer would be mere microseconds after boot-up. “So,” he said heavily, “if you knew about this danger back then—why didn’t you tell us about it?”

Athena sighed, as if he was being silly. “Why, Bud—what good would it have done?”

The newborn Athena, suddenly knowing far more about the future than the humans who had created her, had immediately been faced with a dilemma.

“In January the shield was already all but completed,” she said. “And its design had been, rightly, focused on protecting Earth from the visible light peak energy of the sunstorm. To protect against the particle storm as well would have required a totally different design. There simply wouldn’t have been time to make the changes. And if I had told you that you’d got it all wrong, there was a danger you would give up altogether on the shield, which really would have been disastrous.”

“And even today you didn’t give us the warning until so late. Why?”

“Again there was no point,” Athena said. “Twenty-four hours ago nobody could be sure if the shield would work at all. Not even me! It was only when it was clear that the shield was going to save the bulk of humanity that the particle storm became worth worrying about …”

Gradually Bud began to understand. AIs, even Athena, while they could be far smarter than humans in many ways, were still sometimes rather primitive ethically. Athena had picked her way through the impossible moral maze that confronted her with the delicacy of an elephant trampling through a flower bed.

And she had been forced to lie. She wasn’t sophisticated enough, perhaps, to be able to express her inner confusion openly, but that turmoil had shown up in other ways. Bud’s instincts had been right: Athena, faced with conflicts arising from deep-buried ethical parameters, had been a troubled creation.

“I have always tried to protect you, Bud,” Athena said gravely. “Everybody, of course, but you especially.”

“I know,” he said carefully. The most important thing now was to get through this, to find a solution to this new problem if there was one, not to disturb whatever fragile equilibrium Athena had reached. “I know, Athena.”

Mikhail, frowning, leaned forward. He said carefully, “Listen to me, Athena. You said you had an option. You told Bud we would get through this. You know a way to beat the particle storm, don’t you?”