'She's absolutely right. We've all travelled a hundred and fifty million years down a time contour.'
The Professor didn't bat an eyelid. 'You're both hallucinating!' He dismissed the two girls' explanation.
Tegan obstinately continued with her account of how the 192 had been snared in a time warp. But the Professor was having none of it.
'Unless we get them away from here, this could turn into dementia praecox.' He spoke with the grave authority of a true expert.
The Doctor said nothing. He needed to keep the old boy's confidence; Professor Hayter could lead them to the TARDIS.
'Professor, there's no time to explain.' Captain Stapley was equally pragmatic. 'I need you to show me where I can find the others. And the Doctor has got to get back his ...' He faltered. Let the Doctor convince the old man about the time warp. 'The Doctor must retrieve his equipment,' he concluded with neat circumlocution.
'If you insist, Captain,' Hayter conceded rather ungraciously. 'The prison centre is somewhere on the other side of that hill.'
The little party moved off down the valley. Their breath misted in the cold air and their footsteps crackled on the frosty earth. They instinctively moved fast to keep warm, though everyone kept a wary eye open for a return of the Plasmatons.
As they progressed, Professor Hayter gravitated to the side of Captain Stapely. He felt he could trust the Concorde pilot. He was not so sure about the Doctor, however. The world was full of Doctors with woefully inadequate qualifications; there were several at his own university.
'What is this equipment of the Doctor's?' he asked suspiciously.
Captain Stapley felt like a schoolboy. He couldn't explain how Golf Alpha Charlie had been used to transport an old police box without making himself sound a complete idiot. 'It's a TARDIS,' he said, with confidence he did not feel.
Professor Hayter signalled them to halt at the end of the valley. On the horizon they saw the great pyramid that Tegan and the Doctor had spotted on their earlier exploration. That was where the TARDIS must have been taken, thought the Doctor. With a bit of luck the Professor could show them the way in without drawing attention to themselves.
'How did that get built in this wilderness?' said Captain Stapley, gazing at the Citadel on the horizon.
'Slave labour I expect,' said Professor Hayter bitterly.
The Captain was just wondering how they would ever convince the Professor they weren't in Russia, when Nyssa cried out: 'Doctor!'
She was rigid with fright and fighting for breath.
'Something's happening ... I can't ...' She could hardly mouth the words.
'No!' she screamed, as if trying to ward off an invisible invader.
' It's the radiation,' shouted the Professor. 'I said we should keep away from this place.'
'Keep still!' The Doctor waved back Stapley and Tegan who had moved to Nyssa's help.
They watched Nyssa carefully. She was suddenly calmer.
'Do not approach the Citadel!' Her voice was deep and resonant and seemed to belong to another person altogether. 'Return to your ship ...
There is great danger.'
The Doctor studied Nyssa for a few moments in silence, then spoke as if she were a stranger. 'Who are you?' he asked.
'What's happening?' whispered Captain Stapley, overwhelmed by the sudden transformation of Nyssa's personality.
'The intelligence is using Nyssa as a medium,' explained the Doctor.
'Hysteria triggered by ultrasonics,' sneered the Professor contemptuously, dismissing the Doctor's observations with his own diagnosis.
'Be quiet!' The Doctor turned back to Nyssa. 'Who are you?' he repeated. 'What do you want?'
'Krishnan, krishnan ...' Kalid could see everything in the crystal ball. He had silenced the voices in the Plasmaton mass around the Doctor; now he must silence this girl whose mind was attuned to the Great One.
'Krishnan, krishnan xaraa ...'
Nyssa groaned, feeling pain and despair that were not her own. 'We are
... we are ...' She felt another foree that froze the words in her mouth.
'The control divides
us ...' A dual power struggled for supremacy of her consciousness. 'The control shall be resisted,' the unknown voice uttered again. 'There is so little time. You must resist...'
'Veraam, veraam, xarak namaan!' screamed Kalid inside the Citadel.
'Look!' shouted Tegan. 'It's happening again!'
They all looked up. The Plasmaton cloud had formed in the sky above them. It hovered for a moment, a whirling tongue of white fire, over Nyssa, then slowly descended and swaddled her. She stared out helplessly from the blubbery cage.
'A bioplasmic shield,' observed the Doctor. 'Somebody wanted to stop her talking,' he added more ominously.
'We've got to get away from here,' muttered Hayter, noting that the enemy had more than psychological weapons at its disposal.
'We've got to get Nyssa out of there,' said Stapley. But for all his bravery there was nothing he could to to prise the bonded matter apart.
'I'm afraid we don't have the right kind of energy,' said the Doctor.
'We can't just leave her!'
'We must find the source of the power.' The Doctor looked towards the Citadel.
'You go on, Doctor. I'll stay with Nyssa,' urged Stapley.
Tegan, however, knew that the Captain was far more useful helping the Doctor track down the TARDIS. 'I'll stay with Nyssa,' she insisted.
Hayter was near panic with all this talk going on. 'Continuing to the Citadel is madness!' he cried.
'If we don't get the TARDIS back, we'll be trapped here for ever!' Tegan gave the Professor short shrift for his lack of spirit.
The Doctor agreed with Tegan. 'If Nyssa gets free you are both to go back to the Concorde.'
'You bet!'
'Come on, Captain, Professor.'
Professor Hayter couldn't believe such stupidity. 'Don't you realise the effect will only get worse as we near the centre of the radiation!'
Stapley looked at the Professor in disgust.
The Doctor expressed the Captain's feelings precisely. 'Is that a reason for abandoning your fellow passengers!'
There was no sign of any activity as they neared the Citadel.
While they walked, Captain Stapely thought about what had just happened to Nyssa. He turned to the Doctor. 'If the intelligence was trying to communicate with us, who was trying to stop it?'
That was just what the Doctor was wondering. 'Something with the same resource of psychokinetic energy,' he suggested.
'Another intelligence?'
The Doctor nodded. Captain Stapley could well be right.
'Shamorsherah ... shamorsherom ...'
Though the Doctor and his companions had met with no opposition as they entered the Citadel, Kalid, who saw all things, could observe their approach in the miasmic images that formed and re-formed in the crystal sphere. His face twisted in a horrid smile. Soon they would all be in his power.
The Citadel was a cold, unfriendly place. The dark stone corridors were like tunnels excavated from the bedrock. They crossed and twisted alarmingly. It was as well that Professor Hayter had such an excellent sense of direction.
They advanced deeper and deeper into the Citadel; there was still no sign of anybody.
'The place is deserted,' whispered Captain Stapley.
'Don't you believe it,' answered the Professor. 'Those guards appear from nowhere.'
'Those guards, as you call them,' said the Doctor, 'are fully occupied looking after Nyssa.'
Neither Professor Hayter nor Captain Stapley had any idea what he was talking about.
The Doctor tried to explain. 'Those creatures you saw were particles of protoplasm bonded by psychic energy. The essential protoplasm can take any form.'
'Such as the shield round Nyssa.' Captain Stapley now saw exactly what the Doctor meant.
'Yes. But I suspect that the power and the raw material is limited. So as long as Nyssa is protected ...'
'No Plasmatons!' said Stapley, jumping to the same conclusion as the Doctor.
Professor Hayter wondered why the Captain took such egregious nonsense seriously. The Doctor was a crank.
'I've never heard such an extravagant explanation,' he snorted derisively.
Captain Stapley was irritated by the Professor's reflex scepticism.
Granted the strange forces at work in the place, what the Doctor said made good sense. 'Then how do you explain what happened to Nyssa?'
he challenged the old man.
It was really beneath Professor Hayter's dignity to contribute to such an unscientific debate, but that ridiculous young man needed putting in his place.
'Some form of projection. Maybe part hallucination,' he suggested airily. 'Scientifically speaking ...'
But the Doctor cut him short. 'Scientifically speaking, I'd like you to show me where we can find the others.'
Nyssa felt no fear. There was a womb-like peace within the shield. She could dimly see the face of Tegan, peering forward like an eager child -
nose against the glass of a toyshop window.
'Can you hear me?' Tegan mouthed. 'Are you all right?' '
But Nyssa was a world apart.
'Nyssa ... Nyssa ...' The voice that came to her was inside the shield itself. 'Resistance ... resistance,' it pleaded. 'Kalid shall be resisted!'
'Who are you?' asked Nyssa.
It grew brighter as they turned the corner and saw the end of the tunnel. Captain Stapley led the way forward. Hugging the walls, they tiptoed towards the source of the light.
The corridor ended in a great hall from which radiated several other passages. In the centre of the hall was a large rotunda, forming a room within a room, constructed with much greater precision and of smoother blocks than the surrounding walls.
A large group of men and women were chiselling with crude implements at the tight mesh of stones which concealed the inner room.
'There's Bilton and Scobie!' The Captain had spotted his crew members, mindlessly labouring with the crew and passengers from the 192.
The Doctor's first thought was that Andrew and Roger could lead them to the hiding place of the TARDIS. But he didn't need Professor Hayter to tell him that they had lapsed into a deep, though active, state of trance. It would be quicker to look for it himself. He started to walk round the circular hall.
'If we could separate Bilton and Scobie ...' began Stapley, thinking aloud that it would be relatively easy to bring his copilot and engineer to their senses and, with their help, work on the others.
'Look out for the guards,' cautioned the Professor, who was not a man for heroic gestures.
The Captain tried to reassure him. 'If the Doctor's theory is right ...' He looked round. 'Where is the Doctor?' The Doctor had vanished.
It was the tracks of some heavily loaded sledge or barrow that brought the Doctor into one of the side corridors. If the grooves on the floor had indeed been left by the TARDIS, he needed only to follow the tramlines to the terminal...
One corridor led to another and intersected a third. The Doctor kept going. He finally came to an archway in which was set a door of stone.
Some hidden mechanism swung aside the heavy portal, and the Doctor stepped into Kalid's chamber.
At first he saw nothing of the pedestal in the centre of the room, or the great globe of crystal which rested on it, or the necromantic trappings around the walls. His eyes went straight to the far corner of the chamber -and the TARDIS. He hurried over to it.
'So you are here at last, Doctor.'
The Doctor spun round. The sinister magician had stepped from the shadows behind him.
Captain Stapley walked right round the rotunda inside the great hall looking anxiously for the Doctor.
The Professor bore the Doctor's disappearance with more equanimity.
'I don't know what this Doctor's qualifications are,' - he adopted a tone of voice heard frequently in the senior common room of Darlington University - 'but if you ask me, the man's a lunatic'
'I don't believe I did,' said Captain Stapley.
The passengers and the Concorde crews toiled away at the side of the circular inner room, like marauding
insects assailing the walls of a giant hive. It was a strange sight. Blue-rinsed American matrons, a pop star and his manager, financiers, stewards from the airline: they all applied themselves, without thought of protest, to the interstices of the blocks, uncaring of the debris that rained on their smart clothes.
They took no notice either of Captain Stapley or Professor Hayter.
Stapley watched them in amazement. 'What do you think's behind that wall?' he asked the Professor.
'Another wall, I shouldn't wonder. It's called hard labour.'
The Captain sighed. He started to explain. 'The Doctor's theory is that it's a hi-jack in time rather than space ...'