A space suited paramedic took Joan’s child, blew into its nose, and slapped its backside. A satisfying wail filled the ambulance. The soggy little scrap of flesh was hastily wrapped in a blanket and handed to Joan.

Joan, exhausted, wondering, touched her daughter’s cheek. The child turned her head, and her mouth worked, seeking something to suck.

Alyce was smiling down, sweating and exhausted herself, like any proud aunt. “By God, look at her. She’s already communicating with us, in her way. She’s already human.”

“I think she wants to suckle. But I don’t have any milk yet, do I?”

“Let her suckle anyhow,” Alyce advised. “It will stimulate your body to release more oxytocin.”

Now Joan remembered her classes. “Which will cause my uterus to contract, reduce the bleeding, help expel the placenta—”

“Don’t worry about that,” said a space suit. “We injected you already.”

Joan let the child lick her nipple. “Look at that. She’s making grasping motions. And it’s like she’s stepping. I can feel her feet.”

“If you had a hairy chest she could probably support her weight, and maybe crawl over you. And if you moved suddenly, she’d grab even harder.”

“In case I go bounding off through the trees. Look, she’s calming.”

“Give her twenty more minutes and she’ll be pulling her tongue at you.”

Joan felt as if she were floating, as if nothing was real but the fragile warm bundle in her arms. “I know it’s all innate. I know I’m being reprogrammed so I don’t shuck off this damp little parasite. And yet, and yet—”

Alyce laid her hand on Joan’s shoulder. “And yet it’s what your life has been all about, but you just never knew it before.”

“Yes.”

There was a bleep. Alyce pulled a mobile out of her pocket. Its face lit up with bright images, flickers of movement.

A space suit murmured to Joan. “We’re approaching the hospital. You’re not to be afraid. They have a secure, enclosed entrance.”

Joan cradled her baby. “So Lucy, having just passed through one long dark tunnel, is about to enter another.”

The space suit hesitated. “Lucy?”

“What better name for a primate gal?”

Alyce managed a smile. “Joan, you aren’t the only new parent.”

“Huh?”

“Ian Maughan’s robot worker on Mars has managed to build a fully working replica of itself. It has managed to reproduce. From the tone of this text, he is very happy.”

“He texted you about that?”

“You know guys like that. The rest of the world can go to hell as long as their latest gadget does what it’s supposed to. Oh. The Fourth Worlders killed Alison Scott’s pithecine chimera. I imagine they believed she was an abomination. I wonder what she believed.”

“I suppose she only wanted security, as we all do.”

Joan gazed down at her new baby. One world had begun, just heartbeats ago, while another was ending.

“We came close, didn’t we, Alyce? The conference, the manifesto. It could have worked, couldn’t it?”

“Yes, I believe so.”

“We just ran out of time, is all.”

“Yes. That, and luck. But we must be hopeful, Joan.”

“Yes. We must always be that.”

The ambulance rattled to a halt. The doors banged open and cooler air gushed in. More space suits swarmed around, pushing Alyce out of the way, seeking to get Joan on a stretcher. They tried to take her baby off her, but she wouldn’t let them.

The geologists had long known that Earth had been overdue for a major volcanic incident.

Rabaul 2031 was not the worst eruption known — not even the worst in the historical record. Still, Rabaul had been far more severe than the 1991 eruption of Pinatubo in the Philippines, which had cooled the Earth by half a degree. It was worse than the explosion of Tambora in Indonesia in 1815, which had caused the “year without a summer” in America and Europe. Rabaul was the largest volcanic event since the sixth century after Christ, and one of the largest of the previous fifty thousand years. Rabaul was respectable.

Changes in climate were not always smooth and proportional to their causes. Earth was prone to sudden and drastic alterations in climate and ecology, flips from one stable state to another. The effects of even small perturbations could become magnified.

Rabaul was such a perturbation. But it was not going to be a small one.

It wasn’t really Rabaul’s fault. The volcano was just the final straw. Everything had been stretched to the breaking point anyhow by the humans’ extraordinary growth. It wasn’t even bad luck. If it hadn’t been Rabaul, it would have been another volcano or a quake or an asteroid, or some damn thing.

But as the natural systems of the planet broke down, humans would discover conclusively that they were still, after all, just animals embedded in an ecosystem; and as it died back, so did they.

Meanwhile, on Mars, the little robots worked on. Patiently they turned the wan sunlight and the red dust and the carbon dioxide air into little factories, which in turn produced copies of the robots themselves, with jointed legs and solar cell carapaces and little silicon brains.

The robots transmitted news of their endeavors back to their makers on Earth. No reply came. But they kept working anyway.

Under the burnt orange sky of Mars, generations passed quickly.

Of course no replication, biological or mechanical, could ever be perfect. Some variants worked better than others. The robots were actually programmed to learn — to retain what worked, to eliminate what didn’t. The weaker ones died out. The stronger survived, and carried forward their design changes to the next metallic generation.

Thus variation and selection had begun to operate.

On and on the robots toiled, until the ancient seabeds and canyons glistened, covered by insectlike metal carapaces.

Waking from a cold sleep wasn’t at all like a normal waking, in your own bed, with your wife beside you. It was more like surfacing from a deep dunking in a tank of some clinging, deadening fluid.

But now here was a break in the murk, a widening circle of light centered on a blurry face. The face belonged to Ahmed, the splot — the senior pilot — and not to the CO. That was Snowy’s first indication that something was wrong.

Ahmed was repeating, “OK? Are you OK?”

Before submitting to the injections Snowy had rehearsed how he was going to respond to his wake-up call. He smiled and raised the middle finger of his right hand. “Any landing you walk away from is a good one.” His voice was a rasp, and his mouth was desert dry.

“You aren’t walking yet, smart arse,” Ahmed said grimly.

“Where’s Barking?” Robert Madd, blessed with one of the Royal Navy’s less imaginative nicknames, was the unit’s CO.

“Later,” said Ahmed. He withdrew, letting Snowy see the metal walls of the Pit. He threw a ration pack on the bed. “Get out of there. Help me with the others.”

Snowy — Robert Wayne Snow, age 31 — was a lieutenant in the British Royal Navy, which had given him at least an inclination to follow the odd order. So he struggled to sit up.

The Pit was just a cylinder of gunmetal gray, the walls unadorned save for instrument and sensor consoles. The light came from low-energy fluorescents that cast a sickly glow over everything. The instruments were all dead, just blank screens. It was like being inside an oil tank. And the Pit was full of bunk beds, twenty of them, stacked up. Plastic carapaces lay over the beds. Ahmed was working his way around the room, opening the carapaces one by one, and reclosing most of them.