And it ensured his protection by his cousins now, on this worst day in the long history of humankind, and indeed of apes.

He reached the treetop. In his rough nest of folded-over branches he could still smell traces of his own feces and urine from his last sleep. He fiddled with the branches, pulling away loose tufts of his own fur.

Of course One-eye had no awareness of any of the revolution in human thinking, so crucial for his own survival. But he was aware of other changes. For instance, there was the peculiar muddling up of night and day. Over his head no sun was visible, no sky. Strange fixed lights lit up the forest, but compared with the tropical sun they could cast only twilight—which was why One-eye’s body was unsure whether it was time for him to sleep again, even though it was only a few hours since he had woken.

He lay down in his bed, throwing his long limbs this way and that as he thrashed around to get comfortable. He simmered with inchoate resentment at all these unwelcome changes, a bafflement with which many aging humans would have sympathized. And a bloody image of Tuft filled his mind. His big hands clenched as he considered what he would do to put his younger rival in order.

His scattered thoughts dissolved into a troubled sleep.

Heat and light poured from the high noonday sun, and a storm system that spanned a continent lashed. The dome’s silvered walls rippled and flapped with a sound like thunder. But they held.

Stripped to their underwear, in a living room lit only by a single candle, Bisesa and her daughter lay side by side on thin camping mattresses.

It was hot, hotter than Bisesa, with experience of northwest Pakistan and Afghanistan, would have thought possible. The air was like a thick moist blanket. She felt sweat pooling on her belly and soaking into the mattress underneath her. She was unable to move, unable to turn to see if Myra was okay, or even still alive.

She hadn’t heard Aristotle’s voice for hours, which seemed very strange. The room was silent, save for their breathing, and the ticking of a single clock. It was a big old carriage clock that had been an unwelcome legacy from Bisesa’s grandmother, but it still worked, its chunky mechanical innards immune to the EMP surge while softscreens, phones, and other electronic gadgets had been comprehensively fried.

Beyond the flat there was plenty of noise. There were immense booms and crashes like artillery fire, and sometimes what sounded like rain lashing against a wooden roof. That was sunstorm weather, predicted to follow the huge injection of heat energy into the atmosphere.

If things were this bad under the Tin Lid, she wondered how the rest of the country was faring. There would be flash floods, she thought, and fires, and windstorms like Kansas tornadoes. Poor England.

But the heat was the worst thing. She knew the bleak numbers from her military training. It wasn’t just temperature that got you but humidity. Evaporative heat loss through perspiration was the only mechanism her body had available to maintain its inner homeostasis, and if the relative humidity was too high, she couldn’t sweat.

Above thirty-seven degrees or so, beyond the “threshold of decrement,” her cognitive functions were slowed, her judgment impaired, and her manual and tracking skills weakened. At forty degrees and fifty percent humidity, the Army would have described her as a “heat ineffective”—but she could survive for maybe twenty-four hours. If the temperature was raised farther, or the humidity got worse, that time limit would be reduced. Past that point hyperthermia would set in, and her vital systems would begin to fail: forty-five degrees, whatever the humidity, would see her succumb to severe heat stress, and death would quickly follow.

And then there was Myra. Bisesa was a soldier, and had kept much of her fitness, even in the five-year layoff since her return from Mir. Myra was thirteen years old, young and healthy, but without Bisesa’s reserves. There wasn’t a damn thing Bisesa could do for her daughter. All she could do was endure, and hope.

Lying there, she found she missed her old phone. The little gadget had been her constant companion and guide since she had been Myra’s age, and received her UN-issue communication aid as had every twelve-year-old across the planet. While others had quickly abandoned such desperately uncool bits of gear, Bisesa had always cherished her phone, her link to a greater community than her unhappy family on its farm in Cheshire. But her phone was lost on Mir—on another world, in another level of reality entirely, lost forever. And even if it had been here with her it would have been fried by the EMP by now …

Her thinking was puddled. Was that a symptom of hyperthermia?

With great caution she turned her head to look at her grandmother’s carriage clock. Twelve noon. Over London, the sunstorm must be at its height.

An immense crack of thunder split the tortured sky, and it felt as if the whole Dome shuddered.

43: Shield

1512 (London Time)

Bud Tooke could see the flaw in the shield long before he got to it. You could hardly miss it. A shaft of unscattered sunlight poured down through the skin, made visible by the dust and vapor of the very fabric it was scorching to mist.

In his heavy suit, rad-hardened and cooled, he was skimming under the shield’s Earth-facing surface. He was suspended beneath a vast lens; the whole shield was glowing, full of the light it scattered, like a translucent ceiling. Bud took care to stay in the shadow of the network of opaqued tracks that snaked over the shield, designed to protect him from the storm’s light and radiation.

As he hauled himself along the guide rope—no thruster packs allowed here—he looked back over his shoulder at the maintenance platform that had brought him here, already shrunk to a speck in the distance beneath the vast roof of the shield. He could see no movement, no pods, no robot workers; there was nobody else within square kilometers of him. And yet he knew that everybody available was out and working, as hard as they could, hundreds of them in the greatest mass EVA exercise in the history of spaceflight. It was a perception that brought home to him afresh the scale of the shield: this was one big mama.

“You’re there, Bud,” Athena murmured. “Sector 2472, Radius 0257, panel number—”

“I see it,” he groused. “You don’t need to hold my damn hand.”

“I’m sorry.”

He took a breath, gasping. His suit must be working; if its systems failed, he would be poached in his own sweat in a second. But he had never known a suit to be so damn hot. “No. I’m sorry.”

“Forget it,” Athena said. “Everybody is shouting at me today. Aristotle says it is part of my job.”

“Well, you don’t deserve it. Not when you’re suffering too.” So she was. Athena was a mind emergent from the shield itself; as this terrible day wore on the heat was seeking out the tiniest flaws and burning its way back through panels of smartskin, and with every microcircuit that fritzed, he knew, Athena’s metaphorical head was aching a bit more.

He hauled himself through the last few meters to the rip. He started to deploy his repair kit, a gadget not much more sophisticated than a paint spray applicator that he cautiously poked out into the light. “How is Aristotle anyhow?”

“Not good,” Athena said grimly. “The worst of the EMP seems to be over, but the heat influx is causing more outages and disconnections. The fires, the storms—”

“Time for Plan B yet?”

“Aristotle doesn’t think so. I don’t think he quite trusts me, Bud.”

Bud forced a laugh as he worked. The spray was wonderful stuff, semi-smart itself; it just flowed up over the rent, disregarding the sunlight’s oven heat. Painting this stuff on was easier than customizing the hot rods he used to soup up as a kid. “You shouldn’t take any shit from that creaky old museum piece. You’re smarter than he is.”