Even the rocks were going to die, this time. So here were Henry and his wife, running through the desert and grabbing the rocks and bones, for all the world like the Apollo astronauts during their three brief, precious days on the Moon… Apollo.

Suddenly, as seemed to happen too often these days, he was hit by a jolt of nostalgia. Apollo 11: Moonwalk parties, under clear starry skies, when Henry was eight or nine or ten. God, it seemed a million years ago, a world that was ten degrees cooler, or more, where there were still ice caps, and the new inland sea hadn’t covered over the state of Henry’s birth…

Jane tired first. The cancers and their treatment had left her weakened. She returned to the cool of the car and turned on the radio. Henry could hear the voices of news announcers.

The human world continued to turn. Less news than a decade ago, because less people. The volcanoes and the quakes and the floods and famine and war had killed off all but — the estimates went — around a billion people. Now, numbers were still declining, but more slowly. Almost gracefully.

Less news. Nuclear war in the Balkans. Mutant riots in Asia. There was something about the war crimes trial of Dave Holland, the former British Prime Minister, who, he vaguely recalled, Henry had once met. The trial had finished with Holland being convicted of genocide during that desperate last-ditch British invasion of southern Ireland, mounted from Ulster, Prime Minister Bhide apologizing to the world, a death sentence ordered…

But the murmur of words, emanating in digitized perfection from some satellite, meant little to Henry beside the dusty reality of these ancient rocks.

Henry laboured on as the sun climbed higher in the sky. The sun was surrounded by a Bishop’s Ring, fat and oppressive, volcano ash.

That night they ate their simple meal, and huddled together in zipped-up sleeping bags, and waited for the Moon to rise.

Here it came, fat and full and cloudy, banishing the stars. And as they watched, a fine, white streak flashed across the Moon’s fat equator, a meteor scratch that wrapped itself half the way around the twin planet.

Jane, her head cradled in Henry’s arm, stirred, half-asleep. “Do you think that was Jack?”

“Perhaps.” Or someone else’s child, he thought, falling to the Moon in one of the Arks, the huge, heavy, clumsy mass transports, cushioned by the Moon’s new atmosphere behind a fat aeroshell.

Henry’s outlandish scheme had worked.

It was no less difficult to get out of Earth’s gravity well than it had ever been. But the presence of a braking atmosphere on the Moon had reduced the fuel load the big Arks had to carry by an order of magnitude, and made mass evacuation, of humans and the biosphere, possible. Not only that, he had given them somewhere worthwhile to go.