Another creature counted the names out on his claws. 'We Dugraqs are the arbiters of peace. The Taculbain are secretive and normally have no contact with the other races.'

The Doctor nodded. 'Yes, I was told that the Queen has been . . . kidnapped.'

'That's correct.' The Dugraq sighed. 'Oh, there is so much to tell you.' He tutted and then tapped his third finger. 'Then there are the Rocarbies. They are the boisterous children of our land. They cause trouble, but mean well.'

'Are they the ape creatures that have raided the town?'

'Yes. The magician has made some very rash promises.'

'Foolish man!' chorused a high-pitched voice. The Doctor a.s.sumed that Dugraq to be female.

'You see,' said the leader, 'for many centuries we were the only race to know of the world of light above our heads.

The Taculbain are scared of the light, and never ventured even close to the surface. The Rocarbies worship the Taculbain as G.o.ds.' He snorted. 'They live over there.' A finger stretched into the semi-darkness. It wasn't surprising after all this time below ground that the creatures' senses would be keener than the Doctor's. 'In order to access the tunnels that lead to the surface they would have to tread on hallowed ground.'

'And even the Rocarbies have some some rules,' said the female leader. 'The Taculbain Queen encouraged the superst.i.tions. rules,' said the female leader. 'The Taculbain Queen encouraged the superst.i.tions.

She was clever enough to realize that if the Rocarbies ever saw the Taculbain as mere mortal creatures - flesh and blood like themselves - then a war could break out. If the Rocarbies were to attack them then sheer weight of numbers might lead to the extinction of the Taculbain.'

'We were also quite happy for the Rocarbies not to discover the surface world,' added another Dugraq.

The Doctor nodded attentively, trying to take it all in.

'But there are so many tunnels,' said the pessimist.

'Sooner or later they were bound to discover a way to the surface that avoided the Taculbain.'

'We became worried,' said the leader. 'The status quo was fragile, but working. If the Rocarbies carried on breeding and expanding in numbers . . .'

'They would either swarm on to the surface or deeper into our world.' The speaker shivered slightly.

'So what did you do?' asked the Doctor.

'We have made occasional forays on to the surface world for as long as our legends are old. We decided to warn the people in the light. Unfortunately, the first person we contacted who claimed to be of any importance was Defrabax.'

'The magician?'

'Defrabax the charlatan,' stated the old Dugraq. 'He has all the supernatural powers of a mange-flea.'

'We were tricked,' continued the leader. 'We released the one operational worker to him.'

'Worker?'

'When this land was the surface - when, according to the fables we tell our children, we were slaves in the zoo of the devil-G.o.ds - mechanical workers were used. One remained operational.'

The Doctor smiled. 'So then I was right to think that the homunculus is actually an android.'

The old Dugraq shrugged his shoulders. 'Perhaps. I have heard the term before.'

Another Dugraq continued the story. 'And then Defrabax made contact with the Rocarbies and brought them under his influence.'

'I see,' said the Doctor. 'He asked the Rocarbies to attack the city, presuming that it would be taken as the fulfilment of the legends and prophecies concerning the Menagerie of Ukkazaal.'

'A diversion from his true intentions, which we do not know.'

'And the Taculbain?' asked the Doctor. 'I'm told they too are working for a surface-dweller.'

'We know not who governs their actions,' said the sad Dugraq. 'But recently the Taculbain have discovered that if they emerge on to the surface during dusk or night there is too little light to harm them.'

'There's just one thing I don't understand,' said the Doctor.

The leader chattered in amus.e.m.e.nt. 'Only one?'

'You said that there were four species. What is the other race down here?'

There was a long pause. The Doctor sensed that it was not that they did not want to tell him, but rather that such matters were never trivialized or made light of. When all the Dugraqs were silently staring at their leader he spoke again.

'Deep in this dark city, in a place that we hope the Rocarbies will never find, there exists the other race. These are the creatures that live at the heart of the Menagerie of Ukkazaal. This race has slept for centuries, and must never be awoken. Our legends say that they are awesome killers, evil personified. They are the source of the surface-dweller's own fears and legends. The fourth race are called Mecrim.'

Jamie and Kaquaan stood at the base of the Furnace, overawed by its huge size and blistering heat. It was an enormous, sprawling building, surrounded by muddy pathways and huge piles of timber and coal-bearing rock.

Blackened men with masks and overalls led horses pulling vast wooden sledges. Fuel was taken from the sledges and carried to the furnaces that fed the main generators and turbines, and huge steaming vats of hot ash were rolled away for disposal. Thick cables supported by leaning wooden posts carried the electrical current towards the city.

There was clearly more than one furnace now, but the singular name of the place hinted at the scarlet, boiling haze that pa.s.sed over the area. It was as if some grim G.o.d had set up a forge in which to torture countless souls.

Warm soot speckled down from the chimneys on Jamie and the girl . They almost had to shout to be heard over the sound of the turbines.

'Leaving the castle seemed easy,' said Jamie.

'Good luck,' commented Kaquaan, 'long overdue. Let's find the fat man.'

'How will we -'

'Everyone knows the fat man.'

They walked inside. The multi-level brick building shook with the sound of the pistons. Inside were many more sleighs and carts, the fuel they carried being hurled into the furnaces in a desperate attempt to satisfy their voracious appet.i.te. Huge metal doors swung open at intervals, revealing a bright hot h.e.l.l of fire that was almost painful to look at.

Jamie noticed that no one was bothered by their presence.

Indeed, the young woman seemed familiar to a number of the workers.

They found Argaabil quickly enough. He was truly huge, twice Jamie's width and a foot or two taller. As he turned - a huge hammer, upraised, over an altar - an image flicked through Jamie's mind. This was the man.

Jamie drew the sword, and shoved its tip none too gently towards the man's throat. 'I don't remember you, but I think maybe I ought to,' said Jamie. He pushed the man into a shadowy corner where their business would go undetected.

The fat man went to reach for some object on the floor but Jamie quickly flicked the sword down at his arm, drawing blood. Jamie noticed little nicks in the man's lower arms - the hammer coming down, spraying metal - and glowered at the man. 'This sword is very sharp. Don't try anything stupid.'

The man gulped as the sword returned to his throat. 'I don't - I've never seen you before in my life.'

'I don't believe you,' said the girl. She ran a hand through her badly cropped hair. 'And I'd also like to know who did this to me. Now, you either tell us about your involvement with the Brotherhood of Rexulon, or I let my friend here give your locks a trim, too.'

Jamie moved the sword so that it rested on the fat man's sweating scalp. He was almost blubbering. For all his bulk, thought Jamie, he had a soft heart.

'Please don't tell anyone that I've told you this,'

stammered the man. 'They'll kill me.'

'Have no fears,' said Kaquaan. 'We shall be as silent as a cloudless sky.'

'Swear that you won't -'

'You have the word of a McCrimmon,' said Jamie. 'Tell me what you know.'

'Please understand,' said the man. 'My aims in life are simple. Staying alive is one of them.'

'Your interest in esoteric matters is also well known,' said Kaquaan. 'As is your resentment at working here.' She looked around. 'And seeing this place again I can't blame you for that.'

'Tell us about the Brotherhood of Rexulon,' repeated Jamie.

'I was initiated into the brotherhood months ago,'

whispered the man. 'I hate these infernal machines. That's what the brotherhood is all about, and that's all I'm interested in.'

'When did you first see me?' asked Jamie.

'I was in the chamber. The lady - dear G.o.ds, please forgive me - was on the altar. And my job was to . . .' The man's words were drowned by his sobbing. Jamie couldn't tell if Argaabil was scared of them or frightened of the information he had revealed.

'Who leads the brotherhood?' asked Jamie.

The man shook his head. 'I don't know. Please believe me: I really don't know. But a lot of the knights are involved.'

'How many?' asked the girl.

'About a quarter, I think. A few City Guards, too. And . .

'And?'

'I do know that Araboam is involved.'

Jamie nodded. 'I thought he would be. I have a vague memory of following someone through the corridors of the castle. Perhaps it was him.'

'I saw Araboam when Defrabax's homunculus returned to the wizard's house,' remembered Kaquaan. 'He could have drugged me and moved me from my cell. But this still does not tell us where Cosmae is.'

'The brotherhood have their own cells within Castle Kuabris,' offered Argaabil helpfully. 'There are many secret tunnels within the castle.'

Just at that moment Jamie realized that they were not alone in using the shadows of the power plant to conceal furtive activity. A large bipedal figure was shuffling along a wall, half-obscured by the shadows cast by the gantries overhead. Jamie hushed the man, and pointed the figure out to Kaquaan.

From their vantage point they watched an ape-like creature emerge into a better-lit area, sniffing the air nervously. It crouched down, and placed an object on the wall. Satisfied, it bounded back into the shadows and was gone.

Dragging the man behind them, Jamie and Kaquaan ran over to the device. It was a small silver box with a red panel set into its side that flashed numerals. 'It looks like a bomb,'

announced Jamie with an authority that he hoped was well placed.

'A what?'

'It'll explode,' said Jamie simply.

'Good,' smiled the fat man. 'Bring this d.a.m.ned place down, perhaps. I wasn't aware that the brotherhood had this planned, but no matter.'

'I don't think this has anything to do with the brotherhood,' said Jamie. He spotted another ape on one of the overhead walkways. It too was quietly affixing a device into position.

Jamie placed the sword back into his belt and turned to look at Argaabil. 'I want you to tell all your friends and fellow-workers to clear the area,' he said calmly. 'I don't greatly care what you think about machines. But if we don't get out of here fast, we could all die in the explosion.'

Twelve.

Acting Grand Knight Zaitabor stared down at the dishevelled figure lying prostrate on the floor. He had ordered that Araboam be stripped of his clothing and brought to him under guard. Two knights stood to attention behind the shivering man, staring forward impa.s.sively.