‘We don’t run out the main sails all in one go,’ he was saying. ‘They’d snag and rip. Hirtshal uses the drogue sails first. Do you see them, unfurling about a league away from us? They’ll take up the slack in the lines, get them handsomely taut and aligned, and then we run out the main sails, a thousand square leagues of reflective area.’

He had a way of saying ‘main sails’ that sounded as if the two words were running together.

‘It might seem simple,’ he went on. ‘It’s anything but. The sails are as tricky as they’re delicate.’

Hirtshal was already outside, standing with magnetic boots on the back of the Monetta, using controls that came out through her hull for exactly this sort of operation. If something jammed or tangled, he could sort it out before it got too bad. The launch was ready as well, just in case something got snarled up tens of leagues beyond the ship.

But all was going well. The drogues snapped open, blossoming like sudden chrome flowers, and they in turn helped the unfolding of the main sails, intricate, interlaced arrays of them. I don’t mind saying: it was properly marvellous, the way they gradually opened out, planing apart along seams we’d never have known were there, layer after layer of them, snapping wider all the time. It was like a conjuring trick, something a cove would do in Neural Alley, with cards and a sly gleam in his eye. The sails blazed back at us, each glittering facet silver tinged with red and purple, reflecting the world-filtered light of the Old Sun. The rigging was invisible, but already it was straining to move the ship. In response, Monetta’s creaks and groans had a different sort of music to them. An eagerness, now. The ship was straining, wanting to catch the photon winds.

And so we sailed. Monetta’s Mourn no longer had to slink around on ion thrust, or cower from the gravity well of a swallower. She’d become the thing she was always meant to be: a vessel of the deep void, a creature of the Empty.

That ship of ours was a sunjammer.

Cazaray spun the wheel that opened the door to the bone room.

‘Go in,’ he said quietly. ‘Just don’t touch anything – for now.’

Adrana went in first. I followed on her heels, taking care never to lose my hold on the wall. Cazaray came after us, then closed the door, turning the inner wheel so that it latched itself tight against the frame.

It was quiet in there. I couldn’t hear anything of the life-support system, nothing of the sail-control gear – the occasional whirr and whine of its winches and pulleys had become familiar since the sails were run out – nothing of the usual clamour and chatter of the crew.