The whirring of the rotor died to a gentle tick as they descended into the black pit. The reek, hanging heavier than air at the bottom, stung their eyes. They came alongside the tunnel and the soldiers tossed out grappling hooks, pulling the air-floater up against the steps.

'We're going in,' Fyn-Mah said to the captain. 'Bring five of your men. Scrutator Flydd has ordered me to recover certain.., items from inside. The remaining four soldiers will guard the air-floater.'

The captain shuffled his feet. He looked about fifteen years old and Irisis felt sorry for him. 'I have orders to remain at my post.'

'Those orders are superseded.' She stared him down. 'This mission is for the good of the war, soldier, and we can't do it alone.'

He regarded his boots, glanced up at her, then nodded. 'So you won't mind giving your orders in writing.'

Fyn-Mah took a small piece of paper from her chest pack, scribbled something on it and stamped it with her personal seal. The captain read the document and put it in his wallet.

'Wait here,' Fyn-Mah said to Pilot Inouye. 'If there's danger, go up out of range and keep watch.'

'What if you don't come back?'

'Wait until dawn. If we haven't returned by then, you are released back to your master.'

The underground had a different feeling from Irisis's previous visit. Then it had been a vibrant, working city, still occupied by the lyrinx. Now it was a black, reeking hell where the ceilings had collapsed into heaps of rubble, the floors into fuming sink-holes and dead lyrinx lay everywhere. Fumes wisped down the tunnels like black spectres: sudden winds blew hot and cold; and, always in the distance, was the seething, bubbling crackle of burning tar.

They struggled through into a less damaged area, where they sought for the flesh-formed creature pens for hours without success. Fyn-Mah called out each turn and intersection as they passed it, Irisis noting them down so they could find the way out again. The air here was relatively clean, apart from drifting wisps of fume. Some of the tunnels were still lit by lanterns fuelled with distilled tar spirit, giving the air an oily tang, but they were guttering now.