The cloud poured along the street, more like a fluid than a gas. It must be full of ash, heavier than the air. Lightning cracked within it. It was carrying rocks, irregular, glowing boulders and sharp-edged fragments that probably came from buildings. Carrying all that stuff, she thought, was actually going to make it more efficient at scouring the city as it progressed.

This thing was going to scrape Edinburgh down to the bedrock, she thought, and then the Moonseed was going to eat that. But maybe it would be beautiful, in its way.

So much for reporting in.

She stood tall, facing the heat. She had time for an instant of regret before the cloud reared before her, and—

Soon, it seemed to Henry, the ash had reached a huge altitude, maybe fifty thousand feet. Ash, laden with Moonseed dust.

It obscured the view of Edinburgh, and maybe that was a mercy; he glimpsed the fiery hell of Arthur’s Seat, the husks of burning buildings all around.

The pilot said, “We couldn’t have outrun it, could we, sir?”

“I don’t think so. No.”

“We’ll have to go back to Leuchars. I don’t trust this bird after inhaling all that shit from the air.”

“That’s fine.”

“We’ll find another transport to get you to London.”

Henry looked back at the high ash. It would inject itself all the way up to the tropopause, ten miles above the Earth, where the decreasing temperature of the thinning air was inverted, making the tropopause into an invisible lid on the lower atmosphere. But such was the violence of the eruption, the ash from the Seat would surely break through the tropopause into the stratosphere beyond. There was no rain up there, nothing to wash the debris back down again.

The ash from the Seat would form a thin veil that would spread all the way around the planet, the heavier fragments slowly drifting back down to Earth. He thought he could see, as it reached towards the stratosphere, the steel glitter of Moonseed dust amid the ash.

The genie was out of its bottle now.

“Welcome to Mars, fellas,” he said.

PART III
EARTH

1

Monica Beus was exhausted by the time Scott Coplon, her USGS guide, had led her to Kanab Point, here on the north side of the Grand Canyon. And that after a (reasonably) gentle one-mile hike from the off-road vehicle that had brought them almost all the way from the North Rim entrance station.

It was close to sunset — probably one of the best times of day to view the Canyon — and the light, coming in flat and low from a cloudless sky, filled the Canyon with dusty blue shadow. The layers in the rock shone yellow, orange, pink and red, the colours of fire.