He tried to struggle, but the restraints and drugs held him utterly immobile.

Hiriko sat beside him on a wheeled stool, and consulted a data slate hanging from the side of the gurney.

‘Excellent,’ she said. ‘You’re making wonderful progress, Kai. We should be ready in just a moment.’

Adept Scharff sat opposite Hiriko and Kai saw him insert a screw-plug into the back of his neck, where he could just see the gleam of implanted cognitive agumetics. He took the other end of the cable and plugged it into a featureless black box fitted to the side of the gurney. He smiled at Kai, unspooling a thin cable from the box and snap fastening it to a connective port on Kai’s leather headpiece. His eyes lost their focus for a second, and Kai felt a stab of pressure in the frontal lobes of his brain.

‘Are you in the umbra?’ asked Hiriko.

‘Yes,’ answered Scharff, his voice distant. ‘Ready for your insertion.’

‘Good,’ said Hiriko, and likewise wired herself up to the featureless black box. She too fastened the end of a cable to the apparatus covering Kai’s skull and, once again, he felt the pressure of an invasive presence within his mind.

‘Now,’ said Hiriko. ‘Let us begin.’

She depressed an orange stud on the side of the box, and Kai’s mind filled with light.

THE LIGHT GREW to unbearable brightness, like the surface of a star viewed so close that it would burn his eyes away. Kai screamed, and the light faded until it became tolerable. He found himself standing in the middle of the desert, nothing around him for hundreds of kilometres in all directions. A hot wind feathered the lips of dunes around him, and the hammerblows of the searing sun were a welcome relief after the sterile environment beneath the mountain.

This was his place of safety, this was the Empty Quarter.

Whatever they had done to him hadn’t worked.

Kai knew this wasn’t real, knew it was an artificially conjured dreamscape, and in that realisation, he knew he should not have come here. This was what they wanted. They wanted him here, where his innermost thoughts were laid bare, and his deepest secrets might be revealed.

Though he had professed a desire to tell Hiriko and Scharff what they wanted to know, an unbidden imperative arose in his mind that warned him against that path of least resistance. His life depended on keeping what he had been given secret. Only the man with the golden eyes could be told what he knew, and only by keeping it safe from Hiriko and Scharff would that be possible.

No sooner had he given them names, than he felt their presence in his mind. He couldn’t see them, but he knew they were there. Lurking, waiting for him to lead them to what they wanted to know.

A figure appeared on the sand beside him, a robed woman with long silver-grey hair with eyes that were kind and warm. He knew her, but not like this, not with eyes of flesh and blood. They were emerald green, sparkling and full of life. It seemed perverse to have willingly exchanged such beautiful eyes just to have gained protection from the creatures of the warp.

‘Aniq,’ he said. ‘You’re dead.’

‘You should know better than that, Kai,’ said Sarashina. ‘No one is every really dead so long as someone remembers them. As the great poet said, “that which is imagined, need never be lost.”’

‘Sarashina told me that, but you are not Sarashina.’

‘No, then who would you have me be?’ said the woman, her features transforming in a heartbeat to those of his mother. Her eyes remained emerald green, but where before there was warmth, now there was only aching sadness.

Kai turned away from those eyes, remembering the looks of sorrow every time he and his father had left on another adventure across the globe. He fought to remain dispassionate, but it was difficult in the face of the woman who had raised him and helped shape him into the man he had become.

Except this wasn’t her.

His mother was dead, just as Sarashina was dead.

‘You are Adept Hiriko, aren’t you?’

‘Of course,’ said his mother.

‘Then look like you’re supposed to,’ snapped Kai. ‘Don’t hide behind disguises.’

‘I wasn’t hiding,’ said Hiriko, assuming the form with which Kai was more familiar. ‘I am simply trying to put you at your ease. This process will go much smoother if you don’t fight us. I know you don’t know what Sarashina told you, but I need to find it.’

‘I don’t know where it is.’

‘I think you do.’

‘I don’t.’

Hiriko sighed and linked her arm with his, guiding him towards the gentle slope of a sand dune. ‘Do you know how many psychic interrogations I’ve done? No, of course you don’t, but it’s a lot, and the subjects who fight us are always the ones who end up brain dead. Do you want that?’

‘What kind of stupid question is that?’

She shrugged and continued as though he hadn’t spoken. ‘The human mind is a dizzyingly complex machine, a repository of billions of memories, inputs, outputs and autonomic functions. It’s hard to break into it without causing irreparable damage.’

‘So don’t break in,’ said Kai.

‘I wish that were possible, I truly do,’ said Hiriko with a smile. ‘I like you, but I will tear the meat of your mind apart with my bare hands if I have to. Everyone yields their secrets in the end. Always. It’s just a matter of how much damage they’re prepared to live with at the end of it.’

They reached the top of the sand dune, and Kai found himself looking down at the shimmering fortress of Arzashkun. Its tallest towers wavered in the heat, and Kai shielded his eyes against the reflected glare of sunlight from its golden minarets.

‘Impressive,’ said Hiriko. ‘But it won’t keep me out. Don’t think for a minute it will.’

Kai stopped and turned about, scanning the sands for some sign that they weren’t alone. A suggestion of shadow moving under the sand on a far distant dune flickered at the corner of his vision.

‘Where is Scharff?’ he asked. ‘Doesn’t he join you?’

‘He’s here, but I’m leading this auger.’

Intuition surfaced in Kai’s mind like a sunrise, and a slow smile creased his features.

‘He’s here to pull you out if this gets too dangerous, isn’t he?’

A flash of irritation in her emerald eyes confirmed his insight.

‘You don’t know if you can do this, do you?’ he said.

Hiriko’s grip on his arm tightened. ‘Trust me, I can do this. The only question is how hard you want it to go. I’ll demolish that fortress in a heartbeat, tear down every fictive stone and brick. I’ll break it down to dust and powder until you won’t be able to tell its remains from the sand of the desert.’

She stretched out her hand, and the tallest tower of the fortress began unravelling. What had seemed solid only moments before was now dissolving into smoke and vapour. She clicked her fingers and another tower fell apart. Hiriko met his gaze as she undid in a heartbeat what had taken him years to perfect, but his eyes were on something far distant, something fashioned from dark memory and horror. It pushed through the sands towards them, the predator with the scent of blood in its nostrils.

Kai felt a spike of pressure behind his eyes and Hiriko turned in time to see the dark shape power to the surface of the sand. It came on a tide of blood, a subterranean river violently thrust to the surface of the desert. It roared, this river. It roared and screamed and filled the world with thousands of death cries and agonising last moments. Like a deluge of crimson oil it spilled over the desert, filling the depressions between the dunes with pools of stinking death fluids, washing up their slopes like an angry tide.

‘Is this your doing?’ demanded Hiriko.

‘No,’ said Kai.

‘Stop it,’ ordered Hiriko. ‘Now.’

‘I can’t.’

‘Of course you can, this is yourmind. It bends to your will.’

Kai shrugged as the swelling lake of oily blood rose higher, its surface rippling with the motion of thousands of hands and faces pushing up from below. Until now, Kai had always feared this buried monster, its rages and its guilt, but now the sight of it was a blessed relief. The oozing tide rolled uphill in defiance of hydrodynamics, and gelatinous shapes at last broke the surface of its stinking substance. Tall and thin, with spindly limbs of red scale and volcanic breath, they folded themselves into existence with thin, screeching wails. Their distended skulls formed glossy and horned, their mouths ripped open with jagged fangs.