“Who the hell knows? Come on. Open your bottles and let’s make like we know what we’re doing.”

Blue crouched and, leaning as if reaching out of a boat, began poking at the Moonseed debris with stuff from his equipment pack. He had probes of metal that he scanned over the pool surface or pushed into it, taking data through wires into his backpack, muttering to his tape the whole time.

Ted squatted down beside him, his knees and calf muscles protesting. He got hold of Blue’s belt at the back, near where he had tucked his heavy geologist’s hammer. It was like holding a child, leaning over a rail. Blue didn’t protest.

Ted looked around, back the way they had come. He was on a neck of land like a spit protruding into a silvery sea. At the “shore” he could see the rubble, the ruined Moonscape suburb through which he’d had to clamber. It seemed a long way away. The closest intact building was a way away to the west, halfway up Castle Hill, a squat pile of sandstone that looked like it might once have been St Giles” Cathedral; the old church poked out of the landscape like a beached wreck.

He could see no other humans, in any direction.

In his gloved hand Blue had cupped a small sample he’d taken from the Moonseed surface. “Look at this now. Be careful. It is very delicate.”

Ted bent. He had to wipe the ash from his faceplate to see.

It was like a spider-web; or an autumn leaf; or the skin stretched over the bones of a child’s hand. A fragment of structure, with the finest of membranes stretched between hair-thin spars.

He grunted. “Like something the Wright Brothers might have dreamed of.”

Blue laughed. His hand shook, just slightly, but it was enough to shake the fragment to pieces, to silvery Moonseed dust, which fell through his fingers and back to the pool. “It is all but impossible to retrieve such structures intact. They are like sculptures of dry sand.”

Ted straightened up painfully; it felt as if there was no blood at all in his lower legs. “Structures?”

“Yes.” Blue shifted his position, looking for more samples. “From the aerial shots and samples taken on the ground, it appears that the Moonseed is endeavouring to construct something here. A kind of dish, with a parabolic profile, half a mile across—”

“Covering most of Arthur’s Seat, then.”

“Yes.”

“This Moonseed is a rock-eating germ. How can it construct anything?”

“It does not eat rock,” Blue said, “and neither is it a bug. It moves atomic particles, sometimes molecules, to build structures from the subatomic level up. As far as we can tell, these structures are perfect. Without defect.”

“Not so perfect. That thing in your hands just fell apart.”