Perhaps, it was posited, in all this evolution, the imperatives of the Moonseed had got lost, or warped beyond recognition.

Perhaps the Moonseed was actually a message, of some kind. Perhaps it would rebuild the Solar System, if it was allowed, into some new information-bearing form. Perhaps the Moonseed was trying to reconstruct the world it came from, or the people who lived there. “Like a transporter beam,” said Alfred. A distorted beam, with the information it contained lost or transmuted, into which Earth had strayed. “I think this is just an accident,” Alfred said. “We are lucky—”

That was too much for Bromwich; she snorted. “Lucky? You scientists really are fuckers.” She picked up her papers. “I’ll tell you this, though. If this is what we meet the first time we put our foot out the farmhouse door, we’re going to find it a tough old universe out there.”

David Petit shook his head, disgusted.

The meeting broke up.

The day began badly, and got worse.

Ted even had trouble putting on the thick heat-resistant suit Blue Ishiguro lent him. When he bent to haul on the tight trousers and boots, and wriggled into the one-piece tunic, the stitched-up hole in his chest seemed to gape wide open. And when he pulled on his gloves and the hood with its big glass faceplate, the heat immediately began to gather.

Blue — already suited up, a heavy pack of equipment strapped to his back, cameras fixed to his hood and chest — was watching him sceptically.

“Kind of hot,” Ted said.

“Yeah. Here.” Blue handed him a heavy box, the size and shape of a cat box.

Ted tested the weight. “What’s this?”

“For samples. This is science, remember. How many can you carry?”

Soon Ted was laden with four of the boxes, suspended over his shoulder on leather straps; where the straps dug into him he could feel the heat build up further.

Blue was still watching him doubtfully. Questioning his strength, or commitment.

Ted glanced up at the sun, which was climbing the sky. “Are we going, or what?”

Blue hoisted his pack, picked up tools and sample boxes of his own, and set his face to the north, towards the centre of Edinburgh, the city of ash.

As he toiled over the rubble-strewn ground, Ted kept re-running his last encounter with his daughter. Their last argument.

“…What are you talking about, Dad?”

“They say there are still a few hundred people alive in there. Maybe more.”

“Dad.” It was hard for her to say it, he sensed, as if saying it might make it true. “Dad, Mike is dead. You know Mike is dead. You just want revenge. But revenge against what? The Moonseed?”

No, he had replied. Not the Moonseed. Something more specific than that.

Saying goodbye to her, and Jack, had been harder than he had imagined. But it had to be done. He had a job to do, and he had never shirked from duty before.

Anyway he was too damn old. They didn’t need him any more. It was better this way.

Blue and Ted had been dropped off at the city by-pass, a deserted motorway-class road, a couple of miles south-east of Arthur’s Seat — or rather, of the hole in the ground where the Seat had been. They walked along the Gilmerton Road towards the city, through the residential areas of Gilmerton and Hyvot’s Bank and Inch.

At first there was little sign of damage. Here, the evacuation had been complete: the houses and shops were closed up, and the road was reasonably clear, save for a couple of burned-out wrecks. There was barely a sign, Ted thought, of the calamity that had befallen the city, save for a few inert lumps of rock — lava bombs, said Blue — and the pervasive layer of ash. The ash gave the mundane suburban streets a strange, unearthly tinge, Ted thought, as if the colours had been washed out, only the discarded outlines remaining. And the silence was eerie. No traffic noise. No bird song. No insects.

Only the sounds of the suit, his own noisy breathing, the scuff of the heavy fabric at his armpits and crotch, the soft crunching of his footfalls in volcanic ash.

Like walking on the Moon, he thought.

But the air was still and hot and smoggy, a yellow dome that obscured the sky. There were fires burning somewhere, threads of black smoke that snaked into the sky. And when a road junction gave them a clear view of the Braid Hills, the site of a golf course Ted had played a few times, he could see the steely glint of Moonseed dust.

Blue was dismissive. “That’s a new infection,” he said. “We want to get into the primary nest, where the Seat used to be. See what the hell the Moonseed becomes when it matures.” So he stomped on, setting a tough pace that Ted had trouble matching, even more trouble pretending it wasn’t causing him any distress.

They passed the Cameron Toll, and now, barely half a mile from the Seat itself, the signs of damage suddenly became apparent. Volcanic rubble lay everywhere, rocks and pumice and ash; the housing stock was mostly standing, but with shattered windows and roofs, stove-in cars littering the silent streets.

And now, around Mayfield, they reached a place where the damage was much more severe. The buildings had been effectively razed, down to their foundations. The area looked something like a schematic street plan, in fact.

Blue grunted. “The pyroclastic flow came here. Hell on Earth, for a few minutes or hours.”

The ash was still warm underfoot.

In some places fires had caught, and some of the wreckage was scorched black. The fires had evidently burned themselves out without effective response.

But it was the surviving fragments of normality which were most heart-rending.

Here was a scrap of carpet, lingering beneath a stub of wall, scorched at its fringe, thick with ash. The carpet was strewn with little glass beads. At first Ted vaguely thought this was some kind of volcanic effect, but the beads turned out to be marbles, with the pictures of soccer players embedded inside. Collect all 265! And here was the skeleton of a carefully designed garden, a layout of gravel and a square of scorched earth that had been a lawn. There was no sign of the flowers that might have flourished here, the trees — fruit perhaps — were no more than charred stumps.

Some of the ruins bore pathetic messages, scraps of paper already discoloured by the sun and the billowing ash: notes pleading for Moira or Donald or Petey to meet Janet or Alec or William, at St Giles” or Waverley or the Meadow Park.

The clearing-away of the housing here provided a new, uninterrupted view of Arthur’s Seat itself, off to the north-east. But it was no longer the blunt outcrop Ted had grown up with; now there was little left but a few spiky basaltic spires, cracked and scorched, with a final venting of ash and smoke still curling into the air from its heart.

And everywhere was the cold, unearthly glint of the Moonseed, like a poison that had infected the Scottish earth, emanating from this broken-open old basaltic scab.

Up to this point they had been surrounded by the props of emergency rescue efforts: bulldozers, backhoes, tunnel borers, earth movers, some of them still working. But now they came to a place where no heavy machinery moved: where, amid the Moonseed’s silvery glow, only people picked their cautious way.

Blue had a map tucked into a plastic pouch at his waist. Now he pulled it out and showed it to Ted. It was a large-scale Ordnance Survey, marked by highlighters and pencil. “Listen up,” Blue said. “This is going to be no stroll in the country.”

“I know.”

“I bet you don’t. Here’s what we think. The Moonseed is everywhere: in the ash that coats everything, digging into every exposed chunk of bedrock, working through the subsurface layers. But there are still places we can walk. Places where the surface layers have held together. But they may be—” He was searching for the right word. “Fragile. You have meringues in this country?”