'So, has the young lady been apprehended?' The voice - presumably Zaitabor's - was thick with sarcasm, as if the words were intended for public consumption, but the real meaning was altogether different. Jamie felt the hairs on the back of his neck rising.

'No, Commander. The lady lady must have escaped from the castle.' must have escaped from the castle.'

'What, escaped from Castle Kuabris?' There was a quieter, sn.i.g.g.e.ring laugh. 'That cannot be possible!'

'As jailor, I throw myself on your mercy!'

There was a pregnant pause, and then another storm of laughter.

When it had subsided Zaitabor said, 'It is time.' His voice was cold now, all trace of humour gone.

'Yes, Commander,' said the jailor quietly.

Jamie and Cosmae watched as the two knights marched past their hiding place, oblivious to their presence. A few moments later Jamie set out to follow them. The m.u.f.fled sound of chattering teeth reminded Jamie that his young friend was not far behind.

The bottom part of the ladder was bolted on to the brick wall of an expansive chamber of echoes and reflecting water. From the far end of the room there came the sound of a constant downpour of water, the source of which the Doctor shuddered to contemplate. The lamplight played weaving strands of silver on to the ceiling, but could not even begin to illuminate the full extent of the chamber. The Doctor estimated from the echoes that the room was roughly circular, and a full hundred feet in diameter.

He turned to Himesor. 'You have the map?'

Himesor nodded. 'Despite the legends of the Menagerie occasional inspections were made in the past, before the fumes became too noxious.' Himesor angled the parchment towards his lamp. The Doctor could see his look of concentration through the helmet.

'You spoke of past events,' said the Doctor. 'A sin for a Knight of Kuabris, surely?'

Himesor ignored him, staring at the parchment. After a moment he nodded. 'Ah, Doctor, I see the reasoning behind the route you propose. I wondered at first what complicated scientific process had so accurately plotted a course through the myriad interconnected tunnels and pipes of the sewer.

But now I see. As in the castle, the secrets are always downwards.'

The Doctor nodded, 'Well, it's one possible approach. I don't guarantee that we'll find your Menagerie, but -'

'No matter.' Himesor splashed through the water and towards one of the dark tunnels that led off from the chamber. He could just about fit into it without crouching, but the group would have to move through it in single file.

Himesor drew his sword. Scratches along the edge of the keen blade indicated that, unlike much of the Kuabris armour, this weapon had seen battle.

The Doctor heard the other knights draw their weapons.

He followed Himesor into the tunnel. It descended quickly and was reasonably dry. The brickwork seemed a few hundred years old, no more. There were occasional signs of more recent repair, of mismatching bricks and bright mortar.

The Doctor was about to comment on this when he heard shouts behind him. Two of the knights were poking about their feet with their swords. One was laughing. There was an animal cry, and a rat-like thing shot down the tunnel and past the Doctor and Himesor.

'No real monsters yet,' the Doctor said as Himesor turned to see what all the fuss was.

'This tunnel doesn't go much further,' said Himesor, trudging onwards. 'Then we should be able to -' The Grand Knight stopped for a moment, and looked around him.

'Doctor. These walls.'

'Hmm?' The Doctor walked up to Himesor, and quickly saw the source of Himesor's concern. The rough brick tunnel came to an untidy conclusion, replaced over a few yards by walls of polished and coloured metal. The Doctor ran his hands over them. 'The metal's as smooth as when this corridor was first constructed.'

'Which was?'

'Hundreds, perhaps thousands, of years ago.' The Doctor smiled at the puzzled Grand Knight. 'It is as I suspected.

Your city - perhaps symbolically speaking the cultures of your entire world - is built on the graveyard of a much older civilization.'

Jamie and Cosmae had managed to follow Zaitabor and the jailor for some time without being discovered. On occasions they had been forced to hide from lone knights walking the corridors, but it was clear that they were preoccupied and certainly not expecting infiltrators within the castle.

Despite these interruptions, and Cosmae's anguished expressions of concern that Jamie had quietened, they had not lost track of the two knights. Jamie, used to tracking Redcoats through the heather, had pursued them through the corridors with some skill. It had very quickly dawned on him, however, that the two knights were adopting similarly stealthy tactics. Cosmae had said that Zaitabor was second in command, and presumably the jailor was a knight of some esteem, but both moved like furtive predators. On most occasions they had received the salutes from the other knights that they encountered with dignity, but very occasionally they too had ducked into shadowy alcoves to avoid detection. Jamie was no genius, but he found this very odd.

Jamie and Cosmae turned another corner. The corridor was long and narrow. Jamie estimated that Zaitabor and the jailor should have been no more than halfway down it, but they were nowhere to be seen. There was only one door, at the far end of the corridor.

I suppose that this is one of the corridors within the walls that link the towers,' whispered Cosmae.

'Aye,' nodded Jamie. 'But where can those two knights have gone?' Jamie tried to think the situation through. Either they had disappeared - which would have surprised him only in as much as his travels with the Doctor tended to indicate that such technology was well in advance of what he had so far seen - or they had used a secret door.

'A what?' asked Cosmae when Jamie explained it to him.

'A secret door, a priest hole, a concealed hiding place or maybe a tunnel that connects two rooms.' Jamie smiled.

'The Doctor is very fond of a game called Cluedo Cluedo. That has two secret pa.s.sages, leading from the lounge to the conservatory and . . .'

Cosmae looked at Jamie blankly.

'Och, just help me look, will you?'

The walls were made of cold grey stone, covered by a number of floor-length tapestries on both walls. Jamie's eyes twinkled. Surely it couldn't be this simple? Surely real life didn't work like children's fiction?

'Jamie!' Cosmae was standing by a huge tapestry, depicting a forest glade and a virginal woman in long white robes with a sleeping dragon at her feet. Jamie saw the folds of material move as if in a draught.

'What did I tell you?' exclaimed the young Scot in delight.

He pulled the tapestry back to reveal a small doorway. The door itself had not been closed properly, and a cold wind ran over Jamie's hand as he opened it further. Narrow stairs went down into the darkness.

Jamie began to descend the steep stairway, anxious not to lose too much time in their pursuit of the two knights. The stairs twisted tightly like a corkscrew. Jamie could see the effects of a flickering light of some sort below him, but of Zaitabor and the jailor there was no trace.

The air became colder as they descended, the stairs leading down from the castle and into the rock on which it sat. The stairs eventually led to a small vestibule of naturally sculpted rock. An iron torch-holder had been unceremoniously forced into position just above the doorway. Just inside the room Jamie could see the stairway continuing downwards.

Jamie stepped into the room, Cosmae following close behind. The chamber contained a large number of wooden racks, pushed roughly against one wall, and a small 'window' where the rock had thinned and then collapsed.

The racks contained a large amount of Kuabris armour and a few robes of red cloth, but Jamie and Cosmae were drawn immediately to the window by a noise from beyond.

The window afforded them an excellent view of the huge cave where, presumably, the carved stairway terminated.

The cavern of grey and white rock was hundreds of feet across and roughly rectangular. The floor had clearly been flattened and polished, but most of the rock was untouched, bar the numerous lamps set into the roof Spindly wooden ladders pushed to one side gave an indication of the time and skill needed to light so unaccommodating a room. The lanterns twinkled in the roof like stars in the night sky.

In the centre stood a large altar of what looked like granite. Its sides were decorated with gold leaf and small jewels, although its once smooth upper surface was deeply scarred and stained with a few patches of what appeared to be dried blood.

To one side of the altar stood three semi-circles of hooded figures, their bodies and down-turned faces entirely obscured by the red robes that matched those few left behind on the wooden racks in the small room. The cavern was filled with random whispers and m.u.f.fled sobs.

Facing them was a man in brown robes, his face obscured by a huge insect-like mask. Golden mandibles took the place of a mouth, and multi-faceted eyes glittered in the light like huge diamonds. His hands were raised up towards the heavens, revealing arms covered with scars and crude tattoos. He swayed for a few moments, fists clasping and clawing as if battling with something, and then he let out a huge shriek.

The room became silent and the leader lowered his arms.

A huge man emerged from the shadows, his arms as thick as most men's thighs. His expansive stomach was hidden by a stained overall. A wooden hammer was gripped in one great hand.

As he approached the altar two acolytes came forward carrying, with some difficulty, an ungainly piece of machinery. Jamie did not recognize it, but could identify individual components: there were cogs, belts, valves and pistons. Even the Doctor would have had difficulty identifying the machine, as the moment it was placed on the altar the huge overall-clad man raised the hammer with both his hands and brought it swiftly downwards. Pieces of metal and spring flew off in all directions. The hooded men pressed closer, excitedly throwing the debris back on to the altar.

The hammer came down again, splitting the device in two. Slivers of metal cut into the man's hands but he appeared not to notice. The robed men came even closer to the altar, oblivious to the dangers, sighing as the huge mallet came down again.

The man beat out a slow, dull rhythm with the hammer.

Soon the altar and the floor around it was covered with mangled metal. At a sign from the leader, he stood to one side, staring down at the floor, breathing heavily.

The debris was taken away. The man with the insect mask spoke for the first time. 'The brotherhood salutes you, oh Higher, Hater of Science, Crusher of Untruth, Purger of Legends Not Our Own!'

'Bow before him!' came the reply, the men's voices sounding like the breathing of the caves.

'Let all who stand on this your world quake and seek you now!'

'No past, no future, no word, no tune, no life, no death.'

The cowled figures began to repeat the mantra, some screaming, some whispering. One or two dropped to their knees, whilst others reached upwards, imploring.

'Now!' cried the man in the mask, and there was quiet again. The men rea.s.sembled in their orderly rows, their faces cast downwards. 'Now shall we deal with those who oppose the true ways of the Brotherhood of Rexulon!

Mindful of the evil that the Higher perceives even in our very midst, let us strive to placate him.' With a curt nod a woman was brought forward from the far end of the room.

She was obviously drugged. Two robed men carried her forwards, her bare feet slipping over the floor. She was dressed in a simple black robe, with a white cord around her waist as a belt. Her brown hair had been crudely cut short, gashes in her scalp visible even from Jamie's position. Her eyes occasionally flicked open but her head sagged on to her chest.

As the woman was bundled towards the altar Jamie heard Cosmae gasp in shock. 'It's Kaquaan!' he exclaimed, so loudly that for a moment Jamie feared that the boy's voice would be heard in the chamber below. Cosmae tried to say something else, but it stayed locked in his throat, his lips moving silently. Deathly pale and transfixed, Cosmae stared through the window.

The girl was pulled up on to the altar surface. Although she offered no resistance her arms were held by the two men.

The insect face nodded curtly and the brotherhood watched silently as the large man returned to the altar. He spat on his hands, and then reached for the handle of the huge hammer.

In deathly silence he raised the hammer over his head and prepared to bring it down.

Eight.

Zoe had seen circuses in dramatic reconstructions and on archive film, but never had she expected to join one. She peered out at the audience through a gap in the curtains.

'Is it full?' asked Reisaz.

'Nearly,' said Zoe. She turned to the twins. 'Don't you find it frightening?'

Raitak straightened her jacket, an unusual tension in her movements. 'There are many frightening things in the world. Poverty, illness, hatred. Compared to them, a good crowd is nothing to be feared at all.'

'Mind you,' said Reisaz, 'we both get nervous, if that's what you mean.'

'Some people call it maggots in the stomach,' grimaced Raitak. 'A most unpleasant image.'

'And we're not worried about being called freaks, either,'

said Reisaz. 'The whole purpose of our act is to win over the crowd.'

Zoe parted the curtains again and looked through. The huge tent had been a.s.sembled with remarkable efficiency, and rows of seating stretched towards the roof. People were making their way to the last remaining seats. Mothers and children barely dressed in rags worked their way towards the benches near the ring as besuited gentlemen with tall, dark hats moved earnestly towards the plusher seats further up. Even higher up, gantries were suspended from the roof, people clambering over them like monkeys and settling into position behind large moveable lamps. The generator that powered them was silent beneath the waves of excited chatter.

All but one lamp flicked off, leaving a single dagger of light to illuminate Diseaeda as he walked smartly into the centre of the ring, dressed in an immaculate blue suit. The crowd immediately became quiet and a hushed expectation filled the air. Even from Zoe's vantage point she could tell that Diseaeda was in his element.

'My friends,' he said grandly, his rich voice ringing out as far as the back seats, 'welcome to the first performance of Diseaeda's Travelling Freak Show and Circus. I hope that you have enjoyed looking around the static displays beyond these walls - if not, then there is plenty of time afterwards to sample our selection of tricks, games and monsters. But for the moment, please enjoy tonight's show, and -'

He broke off as a monkey tugged at his sleeve, seemingly impatient for his attention. A second, smaller light illuminated the little creature.

Diseaeda looked down with annoyance. 'Not now,' he said in a loud whisper, 'I'm trying to greet our guests.' The crowd began to chuckle.

Diseaeda straightened and opened his mouth to speak when the creature tugged his jacket again, even more insistently. The monkey chattered and pointed towards the back of the ring.

Another light snapped on, revealing a figure in yellow and pink clothes suspended head-first from the ceiling by a long rope. The rest of the monkeys ran around in tiny circles, shrieking in alarm. The crowd roared with laughter.

Diseaeda stormed over to the hanging man. 'And just what are you doing there?'

'Oh h.e.l.lo,' said the man in a slurred voice. 'I had a little to drink and then . . . Then these monkeys tied me up and . . .