She tried to interrogate the Hams. “Julia, how come you can get through the wind and I can’t?”

An intense frown creased that powerful face. “Hams live here.” She waved her arm. “Still live here.”

“All right. But why am I kept out?”

A shrug.

“What is it I’m not allowed to see? Is there some kind of installation in there, a base? Are the Hams allowed to go up to it? Do you have any, umm, trade with whoever built it?”

None of this meant much to Julia. “Funny stuff.” She waved her fingers before her face. “Hard to see.”

Emma sighed. So the Hams might be wandering around or through some kind of fabulous Homo superior base without even looking at it, interested only in their perennial pursuits, perhaps not even capable of seeing it from out of their bony cages of conservatism.

And that, presumably, was why the Daemons let the Hams wander at will past their meteorological moat. The Hams would restrict themselves, going where they had always gone inside the crater, doing what they had always done, taking not a step beyond their self-imposed boundaries; they would not interfere with whatever projects and designs the Daemons were developing in there. Whereas noisy, curious, destructive Homo sap types like herself would not rest until they had barged their way into the Daemons” shining city.

Breaking this demeaning exclusion became an obsession with her.

She focused on the Hams. She kept trying their trails. She carried Ham tools and weapons as if intent on some Ham-type gathering and hunting. She tried walking in with a party of Hams, her slim form tucked into a line of their great hulking bodies. But the wind seemed to whip through their immense muscular forms, to grab at her and push her aside.

She pushed the deception further. She purloined some skins and wrapped herself up like a Ham. Slouching, bending her legs, she practised the Hams” powerful, clumsy gait. She let her hair grow ragged and filthy, and even smeared clay on her face, letting it dry in a hopeful imitation of a Ham’s bulky facial morphology, the high cheekbones and the bony crest over the eyes.

Then, joining another foraging party, she slouched towards the wind, her gait rolling, keeping her distinctive Homo sap chin tucked into her chest.

The wind wasn’t fooled.

Furious, she stamped back to the caves, and sought out Joshua.

“You have to help me.”

Joshua stared at her. He was ragged, filthy, sitting in a debris-strewn cave that managed to be remarkably ill-appointed, even by the Palaeolithic standards of this Red Moon.

“Wha” for?”

She sighed, forgiving him his squalor, and kneeled in the dirt before him. “/ want to know,” she said. “I want to know what they are doing in there — and who they are. If they are responsible for dragging this Moon around the realities I mean, for changing the sky — I want to know why they are doing it. And to make them understand the damage they are causing, the suffering. Do you see?”

He frowned at her. “Deal,” he said simply.

“Yes,” she said wearily. “Yes, we had a deal. We still have a deal. You help me, and I’ll try to help you get to the Grey Earth. Just as I promised.” God forgive me for lying, she thought.

But his eyes narrowed, almost calculating. “Fin” a way.”

“Yes, I’ll find a way. We’ll go back to the lander and—”

His massive hand shot out and grabbed her wrist. The grip was painful, but she knew that he was using only a fraction of his strength, that if he chose he could probably crush her bone.

“No lies.”

He means it, she thought. He knows my kind too well. “Okay. No lies. I’ll find a way. Get me through the wind wall and I’ll work on it, I’ll find a way. I promise, Joshua. Please, my arm…”

He squeezed harder — just a little — but it was like a vice closing over her flesh. Then he released her. He sat back, baring his teeth in a wide grin. “How?”

“How can I get through the wind wall? I’ve been thinking about that. Whatever controls the wind is too smart to be fooled by appearance. It’s not enough that I look like a Ham. But maybe if I can learn to think like a Ham…”

Scarhead dragged a couple of haunches of meat from the back of the cave. For one brief moment the old guy looked the image of the cartoon caveman. He threw the meat down on the trampled ground, then went back into the cave to fetch tools.

Emma had once more donned her best-effort Neandertal disguise. She got to the ground gingerly, conscious of the need to keep her face rigid so as not to crack her mask of clay.

As usual, nobody showed the slightest interest in her — by now, not even the children.

The meat was, gruesomely, a couple of legs, intact from hoof to shoulder, perhaps from a horse. The limbs were already skinned, fresh, bloody, steaming slightly. Flies buzzed languidly around the exposed flesh.

Scarhead returned. He threw his handfuls of tools on the ground and sat cross legged. He grinned, and the low morning sun made his scar tissue glisten.

She inspected the tools with absent interest. There were limestone pebbles gathered from the beds of rivers, used as chopping tools, and dark basalt blocks shaped into bi-faced hand-axes and cleavers. These were working tools, each of them heavily worn and blood-splashed.

Before she left the Earth she’d known nothing of technology like this, and if she had been confronted with this collection of pebbles and rocks she would have dismissed them as nothing but random debris. Now she knew differently. Tools like this, or the still more primitive artefacts of the Runners, had kept her alive for months.

Scarhead held out a hand-axe to her.

She took the rock, feeling its rough texture. She turned it over in her hands, testing its weight, feeling how it fit perfectly into her small human hand for, of course, Scarhead had chosen it to suit her grip.

Now Scarhead held up a fresh lump of obsidian, hammers of bone and rock. He said bluntly, “Copy.” He grabbed one of the horse legs, and began to saw at the joint between the scapula and humerus, between shoulder and leg. His stone blade rasped as he cut through tough tendons and ligaments.

She tried. Just manhandling the heavy limb proved a challenge to her; the joints were gruesomely stiff, the meat slippery and cold in her hands.

She sighed. “Could I see the vegetarian menu?”

Scarhead just stared at her.

No smart-ass H sap jokes, Emma; today you’re a Neandertal, remember?

She kept trying. She worked the knife into the meat until she had exposed the tendons beneath the shoulder. The meat, cold and slippery against her legs, was purple-red and marbled with fat; it was coldly dead, and yet so obviously, recently attached to something alive.

Turning the stone tool in her hand, she sought to find the sharpest edge. She managed to insert her blade into the joint and sawed at — the tough ligaments, scraping them until they gave, like tough bits of rope.

Scarhead grunted.

Surprised, she raised her hand. The tool’s edge had cut into her flesh, causing long straight-line gashes that neatly paralleled the lifeline on her palm. She hadn’t even felt the cuts happen — but then the blade on a stone knife could be sharper than a metal scalpel; it could slide right into you and you’d never know it. She saw belatedly that Scarhead’s working hand was wrapped in a hunk of thick, toughened animal skin, and a kind of apron was draped over his lap.

…And now the pain hit, sharp and deep like a series of paper cuts, and she yowled. She went to a stream to drench her cut palm in cold water until the slow bleeding had stopped.

Scarhead waited patiently for her, no expression she could read on his broad, battered face.

You aren’t doing too well here, Emma.

She tried again. She spread a skin apron over her lap, and improvised a protective binding for her hand from a bit of tough leather. Then she resumed her work at the ligaments and tendons.