When he’d stomped across the sand beside the Surveyor each disquieting footprint had been blurred into insignificance, but he couldn’t try to complicate this crucial experiment just to obfuscate the issue. He’d always told himself that he’d accepted the true nature of time and choice, and that all he’d objected to in the messaging system was the way it would flatten his deliberations. But even here, with nothing life-changing at stake, the sense of being trapped in the threads of history was more oppressive than it had ever been.

Ramiro’s left arm had grown tired from holding the plant in place over the hole. He shifted it slightly to make himself more comfortable, but as he shifted it back he saw soil rising and adhering to the roots. He stared at this bizarre result for a moment, then decided to stop wasting time delaying an outcome he had no wish to oppose.

He held the trowel to the side of the mound nearest the hole, then drew it closer. The sand followed the blade – not adhering to it and needing to be brought along, but gently pushing it. He lowered the trowel into the hole then withdrew it; the sand parted from the blade and packed itself between the roots of the plant and the side of the hole.

He hesitated, groping for a clearer sense of his role in the task. But what could he actually do wrong? So long as he was committed to making whatever movements with the trowel were necessary until the plant was securely in place, that state of mind and the strictures of the environment ought to work it out between themselves.

He scooped some soil straight into the hole; like the last delivery, it clung to the roots. In Esilio’s terms, this soil had spent at least a few stints packed tightly around the plant; if he could have seen the action in reverse, it would have involved nothing stranger than a clump of sand finally coming loose.

When he was done, Ramiro stood and turned to face Azelio. ‘So now I have to lure half the travellers here in the name of freedom, then leave them to raise their children in a world where everything they do corrodes their sense of agency?’

Azelio said, ‘That’s putting it too harshly. When we get back, all you can do is give an honest account of your own experience. They’ll have seen life under the messaging system, so they’ll already have a better idea than we had about this kind of thing – and which way of life they’d prefer.’

‘The pro-messagers should come here,’ Ramiro declared bitterly. ‘If they want to know the future, let them know it every step of the way. Leave the mountain to us, and we can go back to living with a single arrow.’

‘That’s a nice idea . . . but good luck organising the eviction.’