‘If I disable the safety valves and purge everything in this chamber through the reserve pipes, it would draw a huge surge of energy up from the vents and blast it all through the machinery in this chamber. You wouldn’t need a pressure differential, the quantity of steam and fire generated would flood through the system and trigger an explosion even larger than we planned.’

A massive leg rose into view, clanging down on the edge of the gantry and effortlessly folding the iron guard rail down like crumpled paper.

‘What are you waiting for, El? Do it!’

Eleanora looked at her, and Romilla saw naked terror in her eyes.

‘It will set fire to everything in this chamber the moment the surge comes through. We’ll all burn. Like…’ she trailed off.

Like her father, Romilla thought. Oh Sigmar, why must you be so cruel? Romilla looked up at the glass roof above them. Escape, tantalisingly near yet wholly out of reach. There was a good twenty feet between them and it, and none of the ceiling’s arching gantries was close enough for them to reach. There would be no escape upwards, nor down through the tide of scuttling bodies that converged upon them. There would be no escape at all, she thought. The stark fact of it brought acceptance and sorrow in equal measure.

‘We’ll do it together,’ Romilla said soothingly, placing her hand over Eleanora’s. ‘I am with you. Sigmar is with you.’

Another huge arachnid limb clanged down on the platform’s edge. The gantry gave a terrible moan of buckling metal as it began to tilt under the spider’s weight.

‘All right,’ said Eleanora. ‘Better than… that.’ She threw a series of switches, working with feverish speed. Below, Romilla heard a grinding roar building. Steam howled and whistled. The chamber shook.

As though understanding what was coming, the vast spider redoubled its efforts and the platform tilted harder. Ironwork screamed and tore. In Romilla’s peripheral vision she saw skittering shapes spilling over the railing and stalking towards them. She and Eleanora had killed more than their share of spiders in the last few minutes; their broodmates were wary. She ignored them. She kept her eyes on Eleanora as the engineer flicked a last handful of switches and grabbed a metal dial.

‘Now?’ she asked, shaking.

‘Now,’ answered Romilla.