Jastrabarsk’s Opener had brought along a heavy toolkit that hinged apart to reveal many organised compartments. She was rummaging through the contents while another of Jastrabarsk’s people held up a copy of Loftling’s charts. Above the control panel was a rectangle of neat little pictograms, arranged in vertical columns. A type of language, but nothing I thought I had ever seen before, even in Rackamore’s library.

Over the squawk I heard: ‘Typical Ice Throne stuff. All bluff, no bite.’

‘They’ve bitten us before.’

‘Not this time. If Loftling’s circuit map is righteous, should pick up a power node right about . . . here.’

‘Got it?’

‘On the mark. Good old Loftling. Could someone pass me that inductance coil? No, that’s not the coil. Yes, that compartment. No, the larger one – what do you think we’re trying to get through here, paper?’

I heard a clunk, transmitted through the ground on which I stood. The door heaved open, sliding down into a slot in the base of the trench. We filed into an antechamber where the only light came from our helmet torches, and where the walls were covered in ranks of pictograms.

‘Warnings,’ said the Assessor. ‘Meant to get us all shivery. Abandon all hope for your mortal souls, that kind of thing. I’ve seen worse. We can ignore it all.’

Inside the antechamber was another door that would not function until the outer one had been closed. I did not like the feeling of being bottled in to this ancient, dread place, knowing how few hours remained until the field surface reinstated itself, and we would be trapped. If Jastrabarsk’s Bauble Reader had it right, we would only need to endure for eighteen days before the surface opened again. That would be bearable, provided the lander had enough lungstuff and supplies for us. But Prozor said Quancer was wrong, and that when this window snapped shut, it would be years before the next opening.

Why were we going deeper into this nightmare, when the sane, sensible thing was to get out while we could?

Prozor dropped a hand on my shoulder. ‘Ain’t done this as many times as Mattice or Jusquerel, Fura. The good part is I still remember how wrong it seems, first time out. But being on the ship felt wrong to you at first, didn’t it? Then wearing a suit, going outside? You got used to those things. This is the same. Gets easier.’

‘Thank you,’ I mumbled.

She’d started calling me Fura now, instead of girlie.

Soon we were going down the endless spiral stairs that bored their way into the heart of the sphereworld. In my mind’s eye, I’d seen a descending staircase curving down and out of sight, like the one that threaded the cupola in our house on Mazarile.

It wasn’t like that all, and I was glad not to have been forewarned.