‘And you’re going to wish,’ he whispered, ‘that I had.’

They climbed to the next platform and stopped to let Voriet rest. Nayl kept watch. Drusher and Macks eyed the hurtling gears of the Great Machine all around them with both fear and wonder.

Macks said something.

‘What?’ asked Drusher. It was hard to hear over the clattering roar of the machine.

‘I said it’s giving me a headache,’ said Macks, raising her voice.

Drusher nodded.

‘The noise,’ he said.

‘And the light, and the heat,’ she grimaced. The light shining down from above was brighter than before. It looked sickly and unclean, like the glow of something toxic and contaminating. It made Drusher remember a day, years before, before he had first met Macks, when he’d been caught out in the middle of the steppes of Lower Udar. He had hiked north from a grim livestock town called Kellikow, hoping to find a grazing station the men at Kellikow had mentioned. The station was long gone and derelict, and he’d been looking for alternative shelter when the thunderstorm came in. The light, the whole sky, had turned an extraordinary shade of yellow, a fulminous twilight to herald the fury.

The light filling the tower looked the way the light had done that day. Threatening and unnatural. He’d managed to trudge back to Kellikow, soaked, and spent a week in the infirmary, fighting off pneumonia.

Drusher missed those simpler times.

‘It’s not just that,’ said Voriet from nearby. He was leaning heavily against the metal handrail. ‘The mechanism’s generating an interference pattern. Background psionics. It’s messing with us.’

Macks wasn’t listening. ‘What the hell’s that?’ she asked suddenly. ‘Nayl? Nayl!’

She pointed. There was a figure on a parallel catwalk some distance away. They could just see it, moving out of sight behind part of the Loom mechanism. It was a human figure, walking quite fast, determinedly, arms at its sides.

‘I don’t know,’ said Nayl, moving along the platform to get a better look, gun in hand.

‘Cognitae?’ asked Macks.

The look on Nayl’s face was doubtful.

‘Another one!’ Voriet called out. A second figure had appeared on a platform several stages below them. This one was limping, almost shuffling, but though slower than the first, it seemed equally determined.

‘Get behind me,’ said Nayl.

They turned. A third figure had appeared. It was coming up the steps towards them. It had once been human. It had taken considerable damage to the left side of its body and head. Its flesh was beginning to rot and discolour. Its good eye fixed them with an eager glare. What was left of its face was expressionless.

It was moving fast, striding up the steps and onto the platform.

‘Throne’s sakes!’ Macks exclaimed.

‘Back up!’ Nayl shouted at the advancing thing. He aimed his gun. The figure did not slow down.