Cheers from the polite crowd gathered before the podium, and applause from the group of dignitaries behind Cowley on stage. As the camera panned across their faces Joshua noticed among Cowley’s aides a very young woman – no older than late teenage – slim, dark, sober, smart enough but dressed in what Datum folk tended to call ‘pioneer gear’: leather skirt, jacket over what looked like a hand-me-down blouse. He recognized her; she was called Roberta Golding, from Happy Landings. He’d met her last year at a school in Valhalla, the greatest city of the High Meggers, where, in now-remote pre-Yellowstone days, he and Helen had taken their son Dan as a prospective student. She’d seemed ferociously intelligent then, and if she was working in Cowley’s administration in some kind of position as senior as it appeared at such a young age then she was proving her potential.

Oddly Joshua was reminded of that family he’d helped out of Bozeman not long after the eruption had begun, and how they’d mentioned a ‘sensible young lady’ in ‘pioneer gear’ who’d come around with good advice. Could that have been Roberta herself? The description fitted. Well, as far as he was concerned, the more sensible advice humanity got at a time like this the better . . .

Joshua tuned back into the President.

With the pre-Yellowstone stores exhausted, Cowley said, now was the time to plant the crops and grow the food that would feed them all in the coming winter, and beyond. The problem with that was that the Datum growing season this year was predicted to be brutally short, thanks to the volcanic cloud. And meanwhile the infant agricultural economies on the stepwise Low Earths, none of them established longer than a quarter of a century, didn’t have anything like the capacity yet to take up the challenge. Why, barely a fraction of all that stepwise land had even been cleared of virgin forest yet, on any of the new Earths.

So there would be a ‘Relocation’, a new programme of mass migration, organized by the National Guard, FEMA, Homelands Security, and facilitated by the Navy with their twains. Before the eruption the Datum had hosted more than three hundred million Americans. Now the target would be that no stepwise world would try to support, this first year, more than thirty million – which was about the population of the US in the middle of the nineteenth century. And that meant spreading millions of people further out stepwise, out across a band of worlds at least ten wide, East and West. And, meanwhile, on all the settled worlds they would be ferociously clearing land for agriculture. All of this would have to happen this summer. For sure, Joshua thought, they were going to need whatever tools and hand-me-down clothes and whatnot he and the rest of the reclamation effort could retrieve from the shattered Datum.

‘It will be a movement of people to dwarf the biblical Exodus,’ Cowley said. ‘It will be an opening up of a new frontier that will make the expansion into the Old West look like clearing my grandmother’s front yard. But we are Americans. We can do this. We can and will build a new America, fit for purpose. And I can tell you this. Just as I promised you that nobody would be left behind under the shadow of that infernal ash, so I promise you now: in the difficult seasons ahead, nobody will go hungry . . .’ The remainder of his words were drowned out by whoops and cheers.

‘Have to admit he does this well,’ Joshua said.

‘Yes. Even Sister Agnes says he’s grown into the role. Even Lobsang.’

Joshua grunted. ‘I remember Lobsang predicting a super-eruption, more than once. Blow-ups like that accounted for some of the Jokers we found out in the Long Earth, the disaster-blighted worlds. But he didn’t see Yellowstone coming.’

Sister John shook her head. ‘In the end he had no more insight than the geologists on whose faulty data he had to rely. And he couldn’t have stopped it anyhow.’

‘True.’ Just as Lobsang had claimed to have been unable to avert a terrorist nuclear strike on Datum Madison itself, a decade earlier. Lobsang was evidently not omnipotent. ‘But I bet that doesn’t make him feel any better . . .’

In the sidpa bardo, the spirit body was not a thing of gross matter. It could pass through rock, hills, earth, houses. By the mere act of focusing his attention, the locus that was Lobsang was here, there and everywhere. But increasingly he wished to be at the side of his friends.

Friends like Nelson Azikiwe, who sat in the rectory lounge in his old parish of St John on the Water . . .

Nelson’s host, the Reverend David Blessed, handed him another brimming mug of tea. Nelson was grateful for the warmth of the drink. This was August of 2042, in southern England – less than two years after the Yellowstone eruption – and outside it was snowing. Once again, autumn had come horribly early.

The two of them studied the third person in the room, a local woman called Eileen Connolly, as she sat before the big TV screen, watching the news report as it was repeated over and over. Three days after the assassination attempt at the Vatican, the key audio and visual clips were dully familiar. The deranged scream: ‘Not those feet! Not those feet!’ The horror of the brandished weapon, a crucifix with a sharpened base. The Pope’s frail white-clad figure being dragged away from the balcony. The assassin vomiting helplessly as stepping nausea belatedly cut in.

The would-be assassin was English. His name was Walter Nicholas Boyd. He’d been a staunch Catholic all his life. And what he’d done, single-handed, was to build a scaffolding in Rome East 1 to match precisely the position and height of the balcony of St Peter’s, where the Pope stood to bless the crowds in the Square below. It was an obvious location for a troublemaker, but astonishingly, and unforgivably in these times of step-related acts of terror, the Vatican security people hadn’t blocked it. And Walter Nicholas Boyd had climbed his scaffolding, stepped over with his sharpened wooden crucifix, and had tried to murder the Pope. The pontiff had been badly wounded, but would live.

Now, watching the reports, Eileen began to hum a tune.

David Blessed smiled, looking tired. ‘That’s the hymn they all sing. And did those feet in ancient times / Walk upon England’s mountains green? / And was the holy Lamb of God / On England’s pleasant pastures seen? . . .’ He half-sang it himself. ‘Blake’s Jerusalem. Mr Boyd was protesting against what they are calling the Vatican’s “land-grab”, wasn’t he?’

‘He was,’ Nelson said. ‘In fact there’s a global protest movement called “Not Those Feet”. To which Eileen belongs, does she?’

Eileen, forty-four years old, a mother of two, was once one of Nelson’s parishioners – and was now once more under the care of David Blessed, Nelson’s predecessor, who, in his eighties now, had come out of retirement to care for the parish in these dark post-volcano days.

‘She does. Which is why she’s got herself into such a tangle of doubt.’

‘They are difficult times for all of us, David. Do you think I could speak to her now?’

‘Of course. Come. Let me refresh your tea.’

So Nelson gently questioned Eileen Connolly, taking her through her very ordinary story, her roles as a shop worker and mother – and then the divorce, but life had carried on, she had raised her children well. A very English life, more or less un troubled even by the opening up of the Long Earth. Untroubled, until the aftermath of the American volcano.

‘You have to move, Eileen,’ David said gently now. ‘Out into the Long Earth, I mean. And you have to take your children with you. You know how it is. We all have to go. England is bust. You’ve seen the local farmers struggling . . .’

Nelson knew the score. In this second year without a summer, the growing season even in southern England had been ferociously short. As late as June farmers had been struggling to plant fast-growing crops, potatoes, beets, turnips, in half-frozen ground, and there had barely been time to collect a withered harvest before the frosts returned again. In the cities there was hardly any activity save a desperate effort to save cultural treasures by stepping them away – although there would be a globally distributed, internationally supported ‘Museum of the Datum’ in the stepwise worlds, the governments promised; nothing would be lost . . .