The stairs went around the inside of a very wide shaft, about one hundred spans across, near as I could judge it. They jutted out from the walls, solid enough, and there was sufficient room for three of us to walk side by side. But there was no bannister on the stairs, and as much as I tried to fix my eyes on the next tread below, it was impossible to screen out the view of the stairs continuing on their steeply descending way, curving around onto the opposite face wall, spiralling down into a dizzying dark void. Rackamore’s party had spent most of their time in the bauble either going down or coming up these nightmare stairs, and I began to wonder if I’d the nerves to cope.

We had to move quickly, too. It was no good dawdling. The loot was a league under us, and the pitch of the stairs meant that we had to walk nearly three leagues for every vertical one. In the suits, the best that we could manage was a bit less than half a league per hour, so we would need at least six hours just to reach our prize.

It was worse than that. The effort to make each step got harder the deeper we went, and that was nothing to do with fatigue. I’d spent my life living between the crust of Mazarile and the glass skin of the skyshell, and because of that I’d never been closer than four leagues to the swallower.

When we had gone through the surface door here, there were the same four leagues between us and the swallower. By the time we reached the loot, only three leagues lay under us. That was enough to make us feel as if we weighed more than half as much again, each footfall becoming a leaden effort, each step requiring more care than the last.

Halfway to the core – where there was a house-sized bottle containing the swallower in its magnetic pinch – we’d have walked around under four times our normal weight. Except by then we’d be doing well if we could crawl.

‘The shaft goes a lot deeper,’ Jastrabarsk said, as we gathered our strength for the final twist of the staircase. ‘Maybe all the way down. But if there’s loot stashed much deeper, it’ll stay there until the Old Sun fizzles out.’

‘It’ll be even harder bringing stuff back up the stairs,’ I said, feeling as if my legs had nothing more to give.

‘Hell, to begin with,’ the captain agreed, with a sort of malicious delight in it. ‘But if there’s one consolation, you get lighter as you get higher. Not that you really notice, when you’re down to your last drop of energy. Watch your footing now, Arafura. Seen too many good people trip at the last stage.’