She couldn’t see far inside, though the tiled floor was scattered with rubble and rectangular piles of stone blocks.
Tiaan turned sharply, slowed and darted in between the columns. It was much darker inside and her eyes were slow to adjust. She clipped a cairn of blocks, sending loose stone tumbling across the floor, jolting the thapter sideways.
‘Can you see the shaft?’ she yelled. ‘Irisis?’
Irisis was standing up on the side. ‘No, I can’t. Are you sure this is the place?’
‘I’m sure it’s the one Klarm told me about.’ Tiaan turned in a figure-eight inside the dome. ‘But I’m beginning to think he got it wrong, or his spy did.’ She turned again, her stomach already knotted up. The lyrinx would be here in seconds. ‘He said the air shaft was in the middle but we’ve been across twice and there’s nothing here. We’ll have to go to the next.’
She shot out the other side, but as they passed between the columns Irisis cried, ‘It’s just there.’
Tiaan saw it out of the corner of her eye as well, though too late to stop. The vent was right on the edge, hidden between two walls of stone. The thapter shot into the sunlight and there were lyrinx everywhere. Several landed just outside; others flew in under the dome, and dozens more were approaching. What to do?
‘I don’t dare go back,’ she said. ‘They’d be onto us before we could get the barrel to the opening. We’ll have to try the one with the bellows.’
She shot across the abandoned city, carving a curved trail to the other side, hoping thereby to confuse the enemy about her destination. There were flying lyrinx everywhere now, hundreds of them, and more appearing all the time.
She turned down a broad boulevard where ruined, half-ruined and intact buildings towered on either side, screamed left into a smaller road and turned right into an alley. From there she flew up, soaring over the thoroughfare ahead, turned left again and headed towards a pentagonal pavilion with steepled roofs, set on a stone platform reached by broad steps on all five sides.
‘How do you do it?’ Irisis said.
‘What?’
‘Know exactly where you are, despite all the twists and turns. It’s as if you have the whole map in your head.’
‘I do,’ said Tiaan. ‘The second air shaft is in the building with the steeples. We’ve got to do it this time or they’ll close off all the shafts.’ The sky was dark with lyrinx now.
She roared straight up over the steps, across the forecourt and inside.
‘To the right!’ Irisis yelled in her ear. ‘I can see the bellows.’
Tiaan turned sharply, swept around in a circle and came to a stop directly before the enormous bellows, which consisted of a concertina-like timber and canvas structure, three times the size of the thapter, that was squeezing and expanding, powered by a series of phynadrs. The multiple intakes opened and closed as the bellows worked, directing a roaring blast into a long canvas funnel that ran down into the vent. ‘Nish,’ said Tiaan, ’see where it sucks the air in? I can’t take the thapter in under there – you’ll have to carry the barrel. Hurry!’
He threw himself over the side of the thapter, not bothering with the ladder. Irisis lowered the barrel. Nish heaved it onto his shoulder and ran, staggering under its weight. Irisis fitted a bolt to her crossbow.
Tiaan darted a look over her shoulder. The first lyrinx was already sweeping in. She edged the thapter closer to the bellows.
Irisis fired, so close that the snap of the bow hurt Tiaan’s ear.
‘I hope you got him,’ Tiaan said irritably. Even at close range it wasn’t easy to kill a lyrinx with a crossbow.
‘I got him.’ Irisis was already reloading.
‘Get a move on, Nish!’ Tiaan screamed over the hiss and whoosh of the bellows. ‘They’re here.’
He had reached one of the intakes but was struggling to get the lid off the barrel. The suction of the bellows was so strong that with every blast it pulled him across the floor.
‘I can’t get the lid off,’ he yelled. ‘It’s too tight.’
‘Hold it out to the side,’ said Irisis.
He did so. Irisis took careful aim, fired and the bolt stove the lid in with a puff of spores that was whipped into the bellows intake.
Nish slipped, caught hold of the side then tossed the barrel into the intake. The movement sent him off-balance and he began to slide towards the aperture. Tiaan squeezed her controller