‘Be obedient,’ she said. ‘Shut up and walk. You are very annoying.’

‘So I’ve been told,’ said Drusher. ‘You know, I don’t think I will walk any more. I think, on balance, I’d rather die than submit to these tests you mentioned. I’m not good with pain. I’d rather it was quick.’

He closed his eyes.

There was a sharp crack.

Drusher opened his eyes again. Audla Jaff’s limp body lay at his feet.

‘You took your time,’ Drusher said. ‘I didn’t know how much more crap I could come out with to keep her distracted.’

‘You did just fine,’ said Eisenhorn.

‘Have you killed her?’ Drusher said.

Eisenhorn hunched over her body.

‘Not yet,’ he said.

‘She killed Nayl,’ said Drusher.

‘She has betrayed me on every level,’ replied Eisenhorn. He searched Jaff’s pockets, found Drusher’s gun and held it out to him.

‘I was actually quite pleased to see the back of that,’ Drusher said.

‘Take it, magos. You need to be armed. I think we’re the only two left.’

Drusher took the gun reluctantly.

‘I heard you whisper in my head,’ he said. He rubbed the back of his skull. ‘Right in the back there. It was unpleasant.’

‘I had to signal to you without her hearing,’ said Eisenhorn. ‘I had to get you to stop so I could get close. I didn’t want to risk a shot. It wasn’t easy.’

‘Why?’ asked Drusher. ‘What do you mean?’

Eisenhorn let out a long, slow breath. Drusher could see that his flesh was pallid, and he was perspiring.

‘This place,’ he confessed, ‘this… machine. It’s interfering with my mind. It’s radiating a latent power that’s conflicting with my psykana gifts. It’s taking more effort than usual to use them. And when I do, I can manage short range only.’

‘Then don’t,’ said Drusher. ‘You’ll exhaust yourself.’

‘I’ll use what I have to, magos,’ Eisenhorn replied, ‘when I have to. For as long as I can. My gifts are about the only edge we have over the Cognitae.’

‘What is this machine, inquisitor?’

‘I’m not certain,’ replied Eisenhorn, ‘but I think it’s a device called an Immaterium Loom.’

‘Which is?’

‘It spins things out of the warp,’ said Eisenhorn. ‘It binds the etheric with the physical. There have been rumours for centuries that the Cognitae were trying to build one. I didn’t give those rumours much credence, but yet again the Cognitae dismay me.’

He hoisted Jaff’s limp body upright and glanced at Drusher.

‘Can you support her? It’ll only be for a moment.’

Drusher moved forwards to help.

‘Immaterium Looms are volatile things,’ said Eisenhorn. ‘No one’s ever made one before, though many have tried over the millennia. Heretics and Imperial adepts alike. All prototypes have built up interference patterns with the fabric of reality and imploded.’