‘I don’t need you to tell me how to conduct myself.’ She hefted her pack. ‘We’ll come to a glaciated sheaf soon. We need to get to higher ground so we’re above the ice when we step.’

‘I have done this before, you know …’

And here they were bickering, just as Helen had said they would. Sally walked away from the water, stepping as she moved. Joshua had no choice but to follow her, always just a little behind her flickering, stepping presence.

8

SALLY BROUGHT HIM to Earth West 30. On this particular Earth, here on the Madisonian isthmus, there stood a waterfront development with sodium lights glaring in the light of early evening, and golf carts parked up in rows. It turned out to be a sports lodge, a tourist facility. You got this kind of outfit on ‘significant’ worlds, such as worlds with round numbers: West 30, East 20. And, evidently, volcano winter or not, there were still enough rich folk to support such places.

Nelson Azikiwe, dressed in boots and sensible Low-Earth-type outdoor gear, was waiting for them at the designated spot, just outside the car park.

Sally hitched her pack and looked around disdainfully. ‘Tourists. Outta here. Keep safe, Nelson, Joshua.’

Joshua replied, ‘You too—’

But of course she had already gone, in a pop of displaced air.

Joshua shook hands warmly with Nelson. ‘Thanks for this, buddy.’

‘Well, any friend of Lobsang is a friend of mine – and you and I have known each other a fair time now. It is my pleasure to be your companion on this, the last leg of your long walk. One should not be alone on one’s birthday.’

Nelson’s accent was soft, pleasing, a clipped South African overlaid with crisper British consonants. He seemed unchanged since, Joshua had last seen him, at Lobsang’s memorial, save that at around sixty years old he had perhaps a little more grey in that black hair.

Electronic music began to blare from the lodge, half a mile away. Nelson winced. ‘I think that’s our cue. Shall we take our first step?’

The lodge was whisked away. In Earth West 29 the lake shore was happily virginal.

As he took the impact of the step Nelson managed to stay upright – many poor steppers doubled over with the nauseous reaction, controlled by drugs or not – but Joshua could see discomfort contort his face.

‘Hey, are you sure you want to do this? It’s only a stunt, after all.’

‘Well, Joshua, this is the last stage of your descent from heaven. First you flew like the Holy Spirit through the sky – or like Lobsang’s disembodied soul between incarnations, perhaps. Then you strode boldly with Sally Linsay, a super-powered human. And now for these last few steps you must limp along beside an old man like me, a mere mortal. We will complete our remaining twenty-nine Stations of the Cross before midnight, I assure you. Of course we cannot linger in the radioactive ruin of Datum Madison itself, but I am told that the Sisters at the Home have arranged a small celebration for you, back in West 5. Think cake rather than champagne, however.’

‘That’ll be very welcome.’

‘I think I am recovered. Shall we take another step?’

In West 28 it was raining softly, and though the isthmus itself was empty Joshua could see the lights of a township a couple of miles to the south.

Another step, ten minutes later, and on the rise on which, in Datum Madison, stood the Capitol building – or, since 2030, its ruin – a stone pillar had been erected, with plaque affixed.

Nelson said, ‘In England – where I had my parish, you know – after the Romans had gone, the first Christian missionaries who attempted to convert the pagan Saxons would raise stone crosses in their sparse villages, as tokens of the churches that would one day be built there. Many of the crosses survive, even today. And thus, in the great days of the Aegis, the US administration has scattered its symbols across significant sites like this, in otherwise largely empty worlds. An echo of the future communities to come.’

‘You do see something of the stepwise worlds, then.’

‘Oh, yes – though I have never enjoyed stepping myself. I made one journey into the far Long Earth with Lobsang … But I do enjoy my jaunts into the Low Earths – to be precise the Low Britains. Even today, even after the great emigrations from the Yellowstone winter, those worlds remain largely wild. The lowest dozen or so worlds, to West and East, soaked up the outflow of an estimated half the pre-eruption Datum population, but even West 1 has a population only about the size of the Datum’s around the year 1800. Give us a few centuries and we’ll fill it all up, no doubt. But for now even the Low Earths are echoing halls.

‘And the Low Earths are as the Datum used to be before humans – as they were in the last interglacial, perhaps, before the final Ice Age. Because the trolls and other humanoids stay away from the Datum, even those spin-offs of humanity haven’t affected things much. So Low Earth Britain is a place of oak wildwood, grassland and heathland, a place of water and light, where elephants, rhinos and bears mingle with badgers, deer and otters … Full of wonders from humanity’s lost past. I don’t feel the need to go much further.’

Glancing around, Joshua could see no lights in the gathering dusk. ‘Getting dark already. I have a flashlight.’

‘I also. Let’s go on. We may need to light some brands to keep the local wildlife away later …’

They put in some distance after that, stepping every few minutes, pacing themselves help Nelson get over the nausea.

By West 11 Nelson seemed winded, and ready for a longer break. They sat on a low rise, overlooking another copy of the Madisonian isthmus – but here there was a substantial community, the largest they’d seen so far, a sprawl under a gentle haze of wood smoke with the steady glow of electric lights in some of the windows. Joshua even glimpsed a town sign, standing by a dirt track road:

WELCOME TO MADISON WEST 11

FOUNDED A.D. 2047

POPULATION CHANGEABLE

YOU DON’T HAVE TO BE HOMELESS TO LIVE HERE

BUT IT HELPS

The first house to be seen, just down the trail, was a shack, really, festooned with oil lanterns, and evidently put together from scraps imported from the Datum: plasterboard and roofing felt and plastic drainpipes. Behind the house was a fenced-off expanse of farmland, with what looked like a potato crop, chickens and goats, a heap of roughly cut lumber. A rack of some corrugated plastic material had been set up to face the south where the sun would catch it, with clear plastic water bottles fixed to its surface. Joshua knew this was a cheap way of purifying water; the sun’s ultraviolet would kill off most bugs.

As the two of them sat there a single vehicle came puttering along the track out of town. Driven by an elderly man who tipped a sun-bleached hat to the two of them, it was a flimsy, open vehicle that ran on a purr of electric motors. Once this had been a golf buggy, Joshua guessed, driven by batteries and manufactured from steppable parts – no steel – to be used on the huge golf courses that, before Yellowstone, had colonized the Low Earth footprints of many Datum cities. But now the buggy had a solar-cell blanket draped over its roof, and its cargo looked like milk churns, not golf clubs. In that farm further down the trail, meanwhile, Joshua saw the silhouette of a more substantial vehicle, what looked like a tractor, but with a kind of fat chimney stack fixed to the rear. That was probably a biofuel solution, a gasifier, a gadget that burned wood to release hydrogen and methane as fuel.

Joshua recognized all this. A colony built out of recycled junk from the Datum, Madison West 11 was characteristic of the second great wave of migration out of the suffering Datum Earth.