Icthar considered for a moment. 'The Doctor and Commander Vorshak may remain. Let the others be removed.'

Tegan and Lieutenant Preston were marched out by Sea Devil guards.

'I will listen to what you have to say, Doctor,' said Icthar. 'But I should tell you that we have long abandoned the way of peace and mediation.'

'So it seems. But why? Why is a civilised race like yours waging unprovoked war?'

'Defensive war,' corrected Icthar. 'Silurian law forbids any other. There is a distinction.'

'Defensive war? There's no such thing. When we last met, your leaders were at least prepared to consider living in peace with the other inhabitants of this planet. There are vast portions of the land and of the seas that the humans will never use. At least some of your leaders agreed that there was room for both races. Why abandon such an enlightened policy now?'

'The aim of our policy has always been the peaceful survival of the Silurian race, Doctor. It still is. All that has changed is the means by which it is to be achieved.'

'By actions such as we have seen here? The unprovoked attack on this Sea Base?'

'You forget, Doctor, that twice, at your urging, we offered the hand of peace to these ape-descended primitives. Twice we were attacked and treacherously slaughtered. It will not: happen again.'

'But peaceful co-existence between Man and Silurian is the only way. There is no other solution.' 'There is, Doctor. A final solution.'

The chilling words filled the Doctor with sudden horror. 'Genocide? Everything you Silurians hold sacred forbids it.'

'We shall not destroy the humans, Doctor. The ape-primitives will destroy themselves. We shall merely provide them with the pretext for doing so.' shall not destroy the humans, Doctor. The ape-primitives will destroy themselves. We shall merely provide them with the pretext for doing so.'

Suddenly the Doctor understood everything. 'You're going to fire the proton missiles! Trigger off the war this Base was designed to fight!'

'Precisely, Doctor. And these humans humans will die as they have lived in a sea of their own blood.' will die as they have lived in a sea of their own blood.'

Turlough, at least, had no intention of dying. Like a rat in a trap he would go on struggling till the very last moment.

He was standing on Bulic's shoulders, wrenching desperately at the grille that covered the air-vent. With no other tools than a small penknife, it was a long hard job, but when his own life was at stake Turlough spared no efforts.

There was a noise outside the cell and Turlough sprang to the ground. He heard a familiar voice. 'Get off me!

Leave me alone!' The door was flung open. Tegan and Preston were thrust into the room by a Sea Devil. The door slammed behind them.

Tegan gave Turlough a hug. 'Turlough! You're alive!'

Turlough was in no mood for sentimental greetings.

'Alive and well and trying to escape. Will one of you keep a watch please?'

'I'll do it,' said Preston. She stationed herself at the door.

'Right,' said Turlough. 'Tegan, you help Bulic to lift me up...'

In an amazingly short time, Tarpok came out of the computer bay. 'The primary circuits of the computer are now functioning, Icthar.'

'Can we now activate the missile data banks?'

'We will need the Commander's hand-scan for clearance.'

Vorshak thrust his hands behind his back. 'You'll get no help from me, Silurian.'

A Sea Devil moved forward menacingly, and Icthar said, 'Your hand-scan, Commander. I will not ask again.'

'I suggest you do as he says,' said the Doctor.

'No.' Vorshak stood firm, hands behind his back, quite prepared for a heroic death.

'Listen,' said the Doctor quietly. 'Do you know how strong those things are? They'll manage to use your hand-scan, even if they have to kill you in the process. And remember, while there's life, there's hope.'

Vorshak looked at the Doctor for a long moment. Then, resignedly, he moved to the command console and put his hand into the hand-scan recess.

'Thank you, Doctor,' said Icthar.

Vorshak stepped away from the console and moved closer to the Doctor. 'You know why I gave in?' he whispered. 'Those missiles will never leave the launch pads, not without a synch operator to complete the firing sequence.'

'Don't be too sure of that.'

'I tell you it's impossible, Doctor. That's the way the system is designed. A synch operator is our insurance against an unauthorised missile launch.'

The Doctor indicated a complex piece of Silurian equipment connected to the computer console. 'If my guess is right, that thing is a Manipulator, a little piece of Silurian gadgetry that will more than make up for the lack of a synch operator unless we can do something about it...'

Turlough gave a final heave, and the grille of the ventilation shaft came away. Pa.s.sing it down to Tegan, he jumped down and said, 'Right. The thing to do now is make our way back to the TARDIS.'

'Not the TARDIS the Bridge.'

'What is it about you humans that makes you think there's something n.o.ble about a completely futile gesture?'

Tegan was shocked. 'Turlough!'

Bulic said scornfully. 'You would prefer that we left our colleagues and your friends to die?'

'Look, if there was any real chance of saving them, I'd be the first to go,' said Turlough virtuously. 'But since there isn't...'

'We won't know if there's a chance until we've tried,'

said Tegan. She looked at Bulic. 'Come on, let's go.'

Bulic made his hands into a stirrup and lifted Tegan up so that she could scramble through the gap.

For some time the Silurian called Scibus had been working at the missile console. Now he looked up. 'The missiles are re-targeted, Icthar.'

'Excellent!'

'Launching those things will trigger off a holocaust,'

protested the Doctor. 'You'll destroy everybody.'

'Not everybody. The Silurians will survive.'

'To be masters of a dead world?'

'The world will not be dead, Doctor, only the ape-creatures who have usurped it. Safely hidden away in deep hibernation there waits the remainder of the Silurian race, the true life-force of this planet. When our rightful position is restored, we shall rule the Earth once more.'

Tegan and Bulic had gone from the cell, and Turlough was pacing moodily up and down.

Lieutenant Preston turned away from the door.

'Turlough...'

'What?'

'They'd stand a better chance if we'd gone with them.'

'A better chance of what? Dying? Don't worry, they'll manage that nicely by themselves.'

She looked at him in silence.

'All right,' said Turlough wearily. He formed his hands into a stirrup. 'Put your foot in there and I'll lift you up.'

'What about us, Icthar?' demanded the Doctor. 'Are we going to be included in your final solution?'

'We are a just race, Doctor. Despite the failure of your peacemaking attempts, we bear you no malice. Once we are finished here, you and your companions will be released.'

'And the rest of these people the crew of the Sea Base?'

'They will stay here to die. After all, it will be an act of mercy. Soon there will be no one alive on the surface for them to return to. Commander Vorshak, you will please join me at the command console?'

Vorshak hesitated, looking in anguish at the Doctor.

'Do it, Commander,' said the Doctor gently. Vorshak moved to the console.

Fortunately Bulic had a good knowledge of the Base ventilation system. He led Tegan through a network of air-shafts until they emerged behind a grille in the computer bay which was empty, since Karina's body had been taken away. Bulic kicked out the grille from the inside, climbed through and helped Tegan to get down.

He moved over to the door and opened it a fraction. He could see the Doctor standing a little apart from Icthar and Vorshak at the command console. Two Sea Devil guards stood by the Bridge door.

'They're in there,' whispered Bulic, and Tegan came over to join him.

'Initiate the test firing sequence,' ordered Icthar.

Reluctantly Vorshak put his hand in the scan recess once more, and a flood of data streamed across the read-out screen.

Somehow aware of movement behind him, the Doctor glanced over his shoulders. He saw Bulic peering at him through the door to the computer room, which stood very slightly ajar.

Bulic put a finger to his lips. The Doctor nodded, and the door closed.

'Did he see you?' whispered Tegan.

Bulic nodded. 'I don't know what he's planning, but he'd better hurry it won't be long till they discover we've escaped..

The Doctor glanced at the Sea Devil guards who stood staring impa.s.sively ahead of them. He guessed that any movement towards the Bridge door would alert them immediately. But they didn't seem to be concerned with his movements inside the complex.

Moving casually from instrument bank to instrument bank, studying one set of readings and then another with pretended fascination, the Doctor worked his way round to the door of the computer bay and slipped inside, closing it softly behind him.

Once inside, he exchanged hushed and enthusiastic greetings with Tegan and Bulic. 'Well done, both of you.

Nice timing! Is Turlough safe?'

'Oh yes,' said Tegan scornfully. 'Safely skulking in his prison.'

The Doctor looked up at the open grille. 'Right you are then. Lead on.'

Bulic didn't move. 'Aren't we going to get the Commander out?'

The Doctor shook his head. 'Impossible, I'm afraid. The Silurians need him in there. He'll be watched and guarded every moment.'

'At least we can try,' said Bulic obstinately.

He moved towards the door, but the Doctor put a hand on his arm to stop him. 'We'll rescue your Commander for you but not here, not now. We'll come back for him, I promise. Trust me.'

Bulic looked hard at him for a moment then nodded.

They moved over towards the air-vent.

'Where are we going?' asked Tegan. 'Back to the TARDIS?'

'No, to the chemical store.'

'You've got a plan, Doctor?'

'I'm afraid so. I only hope I won't have to use it.'