With the endless patience of the Silurian race, Icthar, Scibus and Tarpok stood waiting throughout all the long slow process of reactivation.

For what seemed an endless time the ice-shrouded shapes stood motionless, bathed with the warm golden glow of the reactivating ray. Ice melted from great scaly limbs. Icy mists swirled and faded away, as the temperature in the chamber rose steadily. Then, at long last, the Sea Devil Warriors started to come to life.

Slowly, very slowly, they flexed their mighty limbs. Blunt-snouted reptilian heads swung to and fro. Coldly their bulging eyes surveyed the scene around them.

The blunt round heads of the Sea Devils were simpler, more streamlined than those of their elaborately crested Silurian cousins. They lacked the third eye, the source of psychic energy that enabled some Silurians to dominate lesser races by sheer mental force. But if the Sea Devils were simpler, they were also more savage. Their innate ferocity made them terrifying opponents.

Icthar surveyed the awakening Warriors with satisfaction. It was a small group, little more than a raiding party, but it was enough.

Tarpok too was studying the awakening Warriors.

'There will be a short period of orientation, Icthar. Then they will be ready.'

'Excellent. Soon I will instruct our Warriors on the plan of attack.'

One of the Warriors, the leader, was already fully revived. He stepped forward, gazing arrogantly about him.

'I am Sauvix, Commander of Elite Group One.'

'I am Icthar, sole survivor of the Silurian Triad. These are my companions, Scibus and Tarpok.'

Awed by Icthar's rank, Sauvix raised a clawed hand in salute. 'My Warriors are yours to command.'

Icthar stood silent for a moment, savouring the moment. This was the culmination of long years of preparation. After the catastrophe in the caves, when human explosives had sealed up their underground base, Icthar and his fellow survivors had decided to re-enter hibernation. They had slept for more than a hundred years.

When they re-emerged, little had changed in the world above. The ape-primitives were a little more advanced, that was all. But there had been one interesting development.

The ape-primitives had developed new and ingenious weapons of destruction. They had divided into two opposing camps, and in order to continue their incessant warfare they had moved beneath the sea.

The depths of the seas were the territory of the Silurians' marine cousins, the creatures men had called Sea Devils.

Icthar brooded over these things for a very long time.

Then he had evolved a Plan.

Study of ancient Silurian records had revealed the existence of a Silurian battle cruiser, buried deep beneath the polar ice-cap. The s.h.i.+p, its weapons and its crew were alike in hibernation, preserved from the ravages of time, awaiting the moment when they would be needed once more.

Icthar and his companions had located and reactivated the s.h.i.+p. They had taken over the vessel, revived its living weapon, the terrifying Myrka. And now they had successfully completed the most difficult part of the operation: the awakening of Sauvix and his Warriors the Sea Devils.

It had been unwise of the ape-primitives to venture beneath the seas, thought Icthar. Now a terrible vengeance awaited them. It was time for them to relinquish their rule over the planet Earth, to make way for their superiors. The time of the Silurians and of the Sea Devils had come again.

Gravely Icthar raised his hand, returning Sauvix's salute. 'All is prepared, Sauvix. Follow me.'

Disguised in the still-unconscious guard's radiation-suit, which had so conviently and unexpectedly come his way, the Doctor slipped the face-concealing helmet over his head.

He wrinkled his nose in disgust. Clearly, garlic had recently featured in the menu of the Base canteen.

The Doctor looked down at the guard. 'My dear chap, what have you been eating?' he said reproachfully.

Picking up the guard's blaster-rifle, the Doctor hurried on his way.

As Nilson walked unhurriedly onto the Bridge, Vorshak was speaking on the intercom. 'Right, well done! Bring him up here right away.' He turned to Nilson. 'They've captured one of the intruders. He's being brought up here now. I'd like you to be present at the interrogation.'

'Yes, of course. Do we know who they are or how they got in?'

'That's what I'd like you to find out.'

Tegan was running along the corridors, moving, she hoped, in the direction of the TARDIS. Suddenly a helmeted figure appeared around the corner and grabbed her by the arm. Tegan began struggling wildly until the figure pushed back the visor on its helmet to reveal the smiling face of the Doctor. Tegan hugged him delightedly.

'Doctor! I thought you were dead.'

'So did I for a moment! Where's Turlough?'

Tegan explained what had happened. 'The guards must have caught him. We've got to help him.'

'I'd better get you back to the TARDIS.'

'Oh no you don't, Doctor. I want to help find Turlough.'

'All right, all right!'

Tegan sniffed. 'What on Earth have you been eating, Doctor?'

'Never mind that, Tegan. Come along, if you're coming!'

They hurried off.

Sauvix stood beside Icthar, watching proudly as his Warriors filed from the ice chamber.

'How soon will they be ready for combat?' asked Icthar.

'They are ready now,' said Sauvix simply. 'Battle orientation commenced automatically, the instant we revived.'

'Excellent, Sauvix.' He handed the Commander a scroll.

'Here is your plan of attack. Study it well. The ape-primitives' Base must be taken intact.'

The voice of a radiation squad technician was coming from the Bridge intercom.

'Main reactor stabilised, Commander. We now have full power again.'

Vorshak turned from the intercom, as Bulic marched into the room. Behind him, flanked by two armed guards was a thin-faced, sandy-haired young man, clearly the captured intruder. A nasty, treacherous-looking type he was too, thought Vorshak.

The prisoner was brought forward.

Nilson studied him thoughtfully. 'What is your name?'

'Turlough,' said the prisoner sulkily. 'What's yours?'

'I am Nilson. This is Commander Vorshak, senior officer of this Base. Now, I think you had better tell us how you come to be here.'

Turlough jerked his head towards Bulic. 'I've already told him...'

Vorshak stepped forward, looming threateningly over Turlough. 'Now listen, and listen carefully. You have a choice. Co-operate, and tell us all you know and you'll be treated honourably. Should you remain stubborn, you'll be made to co-operate, and it could be a long and painful business. So start talking.'

Turlough was very frightened and fear made him aggressive. 'I've told him and I'm trying to tell you... We are not enemy agents or saboteurs.'

'So why did you try to destroy the reactor?'

'That was the Doctor. There was no real damage. He only wanted to create a diversion so we could get away.'

'Do you really expect me to believe that?'

'If the Doctor had intended to destroy your reactor, it would be lying in pieces at your feet,' said Turlough arrogantly. Tact had never been his strong point.

The Doctor and Tegan turned into a short corridor that ended in a ma.s.sive steel door. The Doctor nodded in satisfaction. 'Good, that must be the entrance to the Bridge. Tegan, you'd better stay here.' He bustled her into a nearby alcove.

'What in the world can I hope to achieve in here?'

'My peace of mind, for a start! Anyway, you haven't got a disguise. Please, Tegan, don't argue.' He bustled her into the alcove. 'Now, I don't need to tell you what to do if anything goes wrong!'

No, he didn't need to tell her, thought Tegan. If anything did go wrong, there was nothing she could do!

'Good luck, Doctor.'

'Thank you.' The Doctor set off.

There was the usual entry-coder by the Bridge door. The Doctor studied it, wondering if he could possibly by-pa.s.s it without setting off an alarm. His problem was simply and unexpectedly solved when the door opened and an off-duty technician hurried out.

Lowering his helmet-visor, the Doctor slipped through the open door, and it closed behind him.

Once inside, the Doctor found himself standing at the entrance to the Bridge complex. There in the middle he could see the main command console. Turlough, flanked by armed guards, was being interrogated by a number of uniformed figures.

The Doctor worked his way un.o.btrusively along the wall.

'The TARDIS is a kind of s.h.i.+p...' said Turlough. 'It's multi-dimensional. I know it doesn't seem to make sense but that's how we got here.'

Nilson said, 'He's insulting our intelligence, Commander. Trying to make us think he's nothing more than a lost tourist!'

'If you had nothing to hide, why didn't you declare yourselves immediately?' asked Bulic.

'We were going to then I accidentally set off an alarm, and the Doctor said we'd better get back to the TARDIS...'

Vorshak turned to Nilson. 'What do you think?'

'He may be telling the truth, Commander, but I doubt it. We can't be sure without delving deeper into his mind.'

Vorshak turned away. 'Then see to it, Nilson. Delve! We must have the truth.'

Nilson nodded to Turlough's guards. 'Take him to the PS unit.'

A guard reached for Turlough's arm.

Suddenly a radiation-suited figure sprang forward, knocked the weapon from the guard's hand and jumped back, swinging a blaster-rifle in an arc to cover the little group. Instinctively Bulic reached for his hand-blaster, but the muzzle of the weapon swung round to cover him.

Pulling off his helmet, the Doctor smiled round the astonished little group. 'Well, gentlemen,' he said cheerfully. 'It seems we have a problem!'

5.

The Attack Continuing her search for the third, and still unaccounted for intruder, Lieutenant Preston and her two guards came down a spiral staircase. She found herself looking at a strange square blue object, a kind of box...

She approached it cautiously and saw that the door was slightly ajar.

'Follow me,' she ordered. Drawing her blaster, she pushed the door open and went inside. She felt a brief moment of disorientation then suddenly she was in an impossibly large control room, with a complex many-sided control console in the centre.

The two guards were gazing around them with dazed astonishment.

She shook her head in sheer disbelief and said weakly, 'Good heavens...' Looking round she noticed another door on the other side of the room. Pointing she said, 'Check through there, and report back.'

The guards crossed the control room and disappeared through the inner door.

Slowly Lieutenant Preston reached for her communicator. This would have to be reported. But what on earth was she going to say...

'Perhaps I should introduce myself,' said the intruder. 'I'm the Doctor.'

Bulic was an experienced combat veteran and he knew that the newcomer's advantage was only temporary. You couldn't hold even a small group of people at blaster-point for ever.

'Your move, Doctor,' he said calmly.