Himesor thumped the table in exasperation. 'What do you mean, she's vanished?'

'She isn't there,' said Zaitabor flatly. 'I've double-checked all the cells myself.'

'I'd have expected more of the guards guards!' spat Himesor. 'A vital prisoner, one who can tell us about the old wizard's homunculus - and she just vanishes from before our eyes.'

'The little man is waiting outside,' said Zaitabor.

'Good to know we haven't lost him yet,' said Himesor.

'Well, you might have done,' announced a sing-song voice from the door. 'But my curiosity demands that I stay.' The two knights turned in surprise. 'Sorry to barge in, but I was getting a bit cold out there in the corridor. And these chains are so very tight . . .' The short man indicated the manacles that locked his wrists together.

'Release the Doctor,' said Himesor.

Zaitabor walked across the room. 'Araboam was supposed to be guarding you!' he said as he turned a small key in the lock on the Doctor's wrist.

'And so he was. But I felt a bit thirsty, and he very kindly went to get me a drink. Maybe that's what happened to that poor girl. Perhaps she just crumbled to dust in one of your cells.'

'You overheard our conversation?' asked Himesor quietly.

'As it turns out, I did,' smiled the Doctor. 'I do have rather good hearing.' The Doctor coughed into his hand as he sat at the great table, and made a show of examining the scrolls that covered its surface. Himesor glared at the man, and pulled them away from him. 'Anyway,' continued the Doctor, 'the girl's disappearance is hardly a secret. All the knights are talking about her.' He suddenly looked up, his eyes fixing on Himesor. 'Some say the Brotherhood of Rexulon took her. After all, she has been contaminated by contact with science.'

'What do you know of the Brotherhood of Rexulon?'

exploded Himesor. 'Everywhere I turn there is talk of the brotherhood. Day by day it seems that the power and influence of the knights is being sucked into the black, bottomless pit that is that cursed, unnatural fellowship! How I long for the whispers of their existence to cease.'

'Tell me about them,' said the Doctor quietly.

'Mere superst.i.tious nonsense.'

'Even so,' said the Doctor. 'Tell me. You were most forthcoming last night. The legends of the Menagerie of Ukkazaal sound most fascinating.'

Himesor's reply seemed as much addressed to Zaitabor as the Doctor. 'The talk of a tired old man late at night.'

'Then you don't want me to help you penetrate the sewers and the menagerie beyond?'

Himesor turned to address Zaitabor. 'Go and find the girl.'

'My Lord.'

The Grand Knight watched Zaitabor as he marched through the door. Just before it slammed there was the sound of shouting. Himesor recognized Araboam's voice, made weak with apology.

'I am intrigued, Doctor,' said Himesor when the noise had subsided. 'You say that you could have escaped from our cells?'

'Oh, I expect so,' said the Doctor casually. 'I'm used to a better standard of straw-filled mattress, if you catch my drift.'

'But you didn't?'

'No. As you will have already realized, I am not a superst.i.tious man. But there is something wrong here, isn't there?'

'Perhaps. Perhaps there is always something wrong here.'

'No, I'm talking about an unusual feeling of fear. I feel as if I'm camped out on the battlefield with an untrained army, waiting to be strafed by an attack plane.'

'Your words are meaningless to me, Doctor.'

'Perhaps. But I think you know what I mean. And that is why I have stayed.'

'Do you know where the girl is?'

'Gracious me, no. But is it possible that one of your own knights could have contrived her "disappearance"?'

'No Kuabris would ever betray the wishes of the Grand Knight.'

The Doctor stared at Himesor. 'I want to help you. I would rather help you from something approaching a position of trust.'

'You are a most unusual prisoner, Doctor.'

The Doctor smiled warmly.

Himesor relented, and spread out his hands in a sign of honesty. 'For your information, Doctor, the Brotherhood of Rexulon are a fanatical sect. They oppose science, as we do, but have no morality, no justice, no breath of the Higher.

And believe me, Doctor, for all our faults, we knights do strive to ensure that the majority of the populace are as content as possible.'

'Thus the power stations.'

'Indeed. But the brotherhood are ruthless, subversive. I have every reason to believe that they are behind these stories of the menagerie. It is in their interest to make the populace believe that we are all being punished for the brief period of scientific experimentation that I sanctioned. That is why we must penetrate the sewers and find out what is down there, to rea.s.sure the people, to destroy any beasts that we find.'

'And creatures are emerging from the sewers, aren't they?'

'That is true.'

'Do you know who the brotherhood are?'

'I am not yet convinced that they exist. Only once has a man admitted to my face that he was a brother - and then only seconds before he hurled himself into the flames of the Furnace.'

'I believe that there is something below this city,' said the Doctor. 'I think that you and I and some of your most trusted men should explore the sewers and beyond, just as you indicated last night.'

'Without the homunculus, how are we to do that?'

'Well, a few moments ago I spoke of trust,' said the Doctor. 'I'm told you have some sacred artefacts, accoutrements of your religion that only the knights have ever gazed upon.' The Doctor smiled his most winning smile. 'I want you to show them to me.'

Diseaeda wiped his brow in the heat, and stared at the motley collection of people shuffling into position on the raised stone dais. The slave market was, as usual, late in starting.

Xaelobran eased himself further back into the folding chair. 'Not long now,' he said. 'Still, I'm in no hurry. Gets me away from the stall for a while.'

'You looking for something?' asked Diseaeda, watching the other buyers move into position.

'Well, ideally I could do with another pair of hands to help out. But it'll depend on the price.'

'Do you remember the last time I was here? Ended up buying Reisaz and Raitak.'

Xaelobran shuddered. 'Those two women, joined at the waist? It isn't natural.'

'That's my trade. Don't suppose I'll see their like here today.'

'Oh, I don't know. If one of my daughters was deformed I'd send her down here as quickly as possible.'

'Compa.s.sion and kindness flow from you like juice from a fruit,' observed Diseaeda.

'Well,' said Xaelobran, 'the way I look at it is this: there's no point eating plants when you're surrounded by carnivores.'

'I have no idea what you're talking about,' said Diseaeda.

'Anyway, the show's about to start.'

A man strode out onto the stage, his clothes formed from interlocking loops of grey leather. A little wooden baton was clenched in one fist, a fat cigar held in the other. His eyes glittered like discovered gold. 'Good people, good people, welcome to the auction. I can promise you the usual selection of waifs and strays, and dutiful servants for the very rich. All the people for sale here have been sanctioned by the guards, who will of course be delighted to a.s.sist you, should your purchases prove unreliable.'

'I just chain 'em to the floor!' shouted one man from the little crowd, to much general amus.e.m.e.nt.

'Now then, good people, without any further inaugural, introductory or dedicatory remarks, let's examine the first item.'

There was something approaching laboured applause from the audience. Diseaeda watched as the man nodded to one of the guards who stood behind the row of people on display. A few words and a prod from a sword encouraged a young boy towards the front of the stage. He looked no more than about eight years old, and it was impossible to tell where his dirty skin ended and his ripped clothes began.

His eyes were as wide as plates, unblinking against the sun.

'This young thing,' said the man, 'has been released to the guards for disposal by the generosity of the Knights of Kuabris. He is a persistent criminal, even when well fed and cared for. You'll have to keep an eye on him, I'll admit, but when he's under your gaze he'll work as hard as anyone.

We're not asking much for him. Will anyone pay seven coins?'

'It would take seven coins just to add extra locks to your 'ouse to stop him escaping,' whispered Xaelobran.

'I'll give you four and a half,' came a voice from the crowd.

'You couldn't buy a dog for under five,' said the slave trader.

'Granted,' came the reply. 'But four and a half's my offer.'

'I'll give you five and a half,' said someone behind Diseaeda, who yawned in boredom. He scanned the men and women waiting to come forward. It pained him to look out for deformities, to almost expect revulsion, but, as he had said, that was his job. They all seemed quite unremarkable, impressively free of even the slightest disfiguring disease.

His attention was drawn to a young woman who stood to one end of the line. She wouldn't have seemed more out of place if she'd been levitating. Although her fingers were blackened and she looked tired, she was otherwise clean, healthy and clearly not of this city. Underneath the anguish Diseaeda saw a bright, open face, surrounded by a smooth cut of shortish, dark hair. Her nose twitched whenever the man waved his arms too vigorously and the cigar smoke came near.

She had a good figure, although her girlishness was in marked contrast to the huge woman who stood next to her, glowering at the crowd. The young girl wore what appeared to be a pair of short trousers and a colourful, long-sleeved top. The fabric alone was enough to fascinate Diseaeda: its colours glowed like gemstones, yet the material seemed light and flexible.

'Some might consider her skinny,' said Xaelobran, noting the direction of his friend's gaze. 'Nice face, though.'

'I could do with another helper,' said Diseaeda.

'Call it what you like,' said Xaelobran.

'She looks very lost. She's obviously not from around here.'

Xaelobran grunted. 'Looks like she's next.'

The man on the stage paused to light another cigar before pushing the young girl forward. 'What am I bid for this little creature?' he asked.

The Most Holy Place was deep in the bowels of the rock on which the castle sat. The Doctor fancied that he could almost hear the towers above them sonorously grinding down into the dark stone. Certainly the sounds of conversation, the clink of armour, the background hum of chanted meditation, had subsided. Even Himesor had fallen silent, doubtless still wondering if he had made the right decision.

These tunnels had been carved out of rock and elaborately engraved. Despite their impressive structure a soft wind scurried around their feet and up into the vaulted ceiling.

Electric lights had been placed in the ornate holders that had presumably once held burning torches.

The warren of tunnels baffled the Doctor. The carved patterns were in a regular sequence and therefore could not also function as direction or location markers. And yet at each junction Himesor barely paused before pressing on.

A few moments later the Doctor realized what the secret was. At each intersection, Himesor took the tunnel that led down. The Most Holy Place seemed to be as deep under the castle as was possible.

'I'm sorry that no trace can be found of either of your friends,' said Himesor suddenly.

'Perhaps they've already escaped,' said the Doctor.

'They're very resourceful. Anyway, I am grateful to you for trying.'