'Now I am alarmed, friend.'

'Yes. Well, what shall we do, Icarium?'

'Do we have any choice?' With that, the Jhag strode through the barrier.

Mappo sighed, then followed.

Only to be clutched at the shoulder and pulled back from a second step – which, he saw, would have been into empty air.

The cavern before them was vast. A bridge had once connected the ledge they stood on to an enormous, towering fortress floating in space, a hundred or more paces opposite them. Sections of that stone span remained, seemingly unsupported, but others had broken away and now floated, motionless, in the air.

Far below, dizzyingly far, the cavern was swallowed in darkness. Above them, a faintly glittering dome of black rough-hewn stone, like a night sky. Tiered buildings rose along the inner walls, rows of dark windows but no balconies. Dust and rubble clouded the air, none of it moving. Mappo said nothing, he was too stunned by the vista before them.

Icarium touched his shoulder, then pointed to something small hovering directly before them. The coin, but not motionless as it had first seemed. It was drifting away, slowly. The Jhag reached out and retrieved it, returning it to the pouch at his waist. 'A worthy return on my investment,' he murmured. 'Since there is momentum, we should be able to travel. Launch ourselves from this ledge. Over to the fortress.'

'Sound plan,' Mappo said, 'but for all the obstacles in between.'

'Ah, good point.'

'There may be an intact bridge, on the opposite side. We could take one of the side passages behind us. If such a bridge exists, likely it will be marked with a silver barrier as this one was.'

'Have you never wished you could fly, Mappo?'

'As a child, perhaps, I am sure I did.'

'Only as a child?'

'It is where dreams of flight belong, Icarium. Shall we explore one of the corridors behind us?'

'Very well, although I admit I hope we fail in finding a bridge.'

Countless rooms, passages and alcoves along the wide, arched corridor, the floors thick with dust, odd, faded symbols etched above doorways, possibly a numerical system of some sort. The air was stagnant, faintly acrid. No furnishings remained in the adjoining chambers. Nor, Mappo realized, any corpses such as the one Icarium had discovered in the mechanism resting on the lake-bed. An orderly evacuation? If so, where had the Short-Tails gone?

Eventually, they came upon another silver door. Cautiously passing through it, they found themselves standing on the threshold of a narrow bridge. Intact, leading across to the floating fortress, which hovered much closer on this, the opposite side from whence they had first seen it. The back wall of the island keep was much rougher, the windows vertical slashes positioned seemingly haphazardly on the misshapen projections, crooked insets and twisted towers.

'Extraordinary,' Icarium said in a low voice. 'What, I wonder, does this hidden face of madness reveal of the makers? These K'Chain Che'

Malle?'

'A certain tension, perhaps?'

'Tension?'

'Between,' Mappo said, 'order and chaos. An inner dichotomy, conflicting impulses…'

'The contradictions evident in all intelligent life,' Icarium said, nodding. He stepped onto the span, then, arms wheeling, began drifting away.

Mappo reached out and just managed to grasp the Jhag's flailing foot.

He pulled Icarium back down onto the threshold. 'Well,' he said, grunting, 'that was interesting. You weighed nothing, when I had you in my grip. As light as a mote of dust.'

Slowly, tentatively, the Jhag clambered upright once more. 'That was most alarming. It seems we may have to fly after all.'

'Then why build bridges?'

'I have no idea. Unless,' he added, 'whatever mechanism invokes this weightlessness is breaking down, losing its precision.'

'So the bridges should have been exempted? Possibly. In any case, see the railings, projecting not up but out to either side? Modest, but sufficient for handholds, were one to crawl.'

'Yes. Shall we?'

The sensation, Mappo decided as he reached the midway point, Icarium edging along ahead of him, was not a pleasant one. Nausea, vertigo, a strange urge to pull one's grip loose due to the momentum provided by one's own muscles. All sense of up and down had vanished, and at times Mappo was convinced they were climbing a ladder, rather than snaking more or less horizontally across the span of the bridge.

A narrow but tall entranceway gaped ahead, where the bridge made contact with the fortress. Fragments of the door it had once held floated motionless before it. Whatever had shattered it had come from within.