'Not so much of the petty,' said Kurt.

'I thought we agreed there was no need for this,' said the Doctor steadily. 'As you well know, I value all my friends, and I'll do what I must to save them.'

He went over to the console and set to work. Steg watched him as he moved from control to control, touching each glowing projection in turn with his palm.

'How much longer?' rasped Steg impatiently.

'Not long. The effect should be visible quite soon.'

'Fetch me the field transmitter,' ordered Steg. Two troopers appeared carrying a heavy piece of communications equipment.

Steg began talking into it, in low, urgent tones. 'Yes, very soon now, Admiral. I suggest that you take position. Thank you, sir. And good fortune to you.'

Steg went over to the Temple doorway and stood looking upwards. Above him the sky began to darken. On a sudden impulse Steg called, 'Gather the prisoners in the doorway here so they may see our triumph. Kill anyone who tries to escape.'

Herded into the doorway by Sontaran troopers, the mystified captives joined Steg in looking upwards at the sky.

The Doctor, his work apparently finished, came to join them.

The sky continued to darken, not all over but in a clearly defined area. Soon there was a great circle of darkness, not unlike the effect produced by an eclipse.

A s.p.a.ceship appeared, heading for the circle of blackness.

The ma.s.sive wheel-like structures either side of the huge central dome gave it the appearance of a mighty juggernaut, rolling remorselessly through s.p.a.ce.

'The War Wheel,' breathed Steg. 'Now watch.'

The War Wheel rolled into the circle of darkness and disappeared. The dark circle faded, and the War Wheel had gone.

Steg turned to the Rutan, hovering in the doorway beneath the menace of Sontaran blasters. 'You have seen the doom of your miserable race, Rutan. Now we wait.'

'Wait for what?' demanded Bernice.

'For the Rutan to die, or to go mad. It will be interesting to see which occurs first.'

Bernice turned to the Doctor and discovered that while everyone, guards included, was staring in fascination at the sky, he had slipped back to the Rutan console and was working at frantic speed. His hands flew over the crystal controls in a series of increasingly complex movements. He finished at last and came back to join the others, his face calm and resigned.

'What's happening, Doctor?' whispered Bernice.

'Well,' said the Doctor, 'it's simple enough, really.'

Steg held up his hand. 'Please, Doctor, allow me my moment of triumph.' He addressed his a.s.sembled captives.

'What you have just witnessed is the opening, and closing, of a wormhole a hypers.p.a.ce tunnel through normal s.p.a.ce. Long ago, the Rutans discovered that the wormhole linked their home world and Sentarion. They saw it as an escape-route a bolt-hole for their supreme ruler, the Great Mother, repository of the group consciousness that links all Rutans. They forgot that a tunnel runs two ways. The War Wheel will emerge from the wormhole on the Rutans' home planet. There it will destroy the Great Mother and when the Great Mother dies, every single Rutan will either die or go mad.'

The Rutan gave a great shriek of pain.

Steg laughed. 'We shall attack in force, and the Rutans will be powerless to resist us. The Rutan Empire will be finished.

Then we shall bring Sontaran discipline to the rest of the galaxy. Is my exposition correct, Doctor?'

The Doctor said, 'Almost.'

Something in his voice sent a chill of fear through Steg's heart. 'What do you mean almost?'

'You are a.s.suming that the War Wheel will leave the wormhole.'

'What do you mean? It has entered, it will leave.'

'Hypers.p.a.ce travel is almost instantaneous,' said the Doctor. 'Shouldn't our Rutan friend be going a bit green by now? How do you feel, Karne if I can call you that?'

'We feel nothing. Nothing has changed.'

'Nor will it,' said the Doctor. 'The Great Mother is safe.

The Sontaran plan has failed.'

Steg thrust his way through troopers and captives until he confronted the Doctor. 'Why has it failed, Doctor?'

'I told you that the Rutan device was a simple warping template? It was a simple matter to reverse the polarity. The worm has swallowed its tail, Steg. Its entrance is now an infinite time from its exit. The War Wheel can never emerge.

It will journey on for ever.' He turned to the Rutan. 'There's a price to pay, of course. The wormhole can never be used again. You must find some other way to safeguard your Great Mother. And it's time you stopped playing s.p.a.ce-G.o.ds with the Sentarrii and allowed them to develop alone.'

There was genuine puzzlement in Steg's voice. 'You did all this, Doctor? You tricked and defied me, knowing that it meant certain death for you, and for all your friends?'

'You know who I am, Steg. Did you really think you could intimidate me?'

'I underestimated you, Doctor,' said Steg in a low voice.

'But perhaps you also underestimated me. Did you perhaps think I should spare you, now that all is lost?'

'Why not? Surely vengeance is pointless now.'

'It is all I have, Doctor. All that you have left me.'

'Then spare my friends. I am the one who defeated you.'

'I am defeated and disgraced,' said Steg. 'But I am a Sontaran, Doctor. I shall play the game out to the end.' He raised his voice in command to his troopers. 'Kill the prisoners. Kill them one by one, the Doctor last. Let him see his friends die.' He pointed to Bernice. 'Begin with this one!'

'No!' bellowed the Lord Chancellor.

Ignoring him, the trooper nearest Bernice raised his blaster.

The Lord Chancellor swooped down from his enormous height, seized the trooper in powerful foreclaws, and bit off his head.

The terrified troopers opened fire and the Chancellor fell.

Immediately the other Sentarrii, the Chancellor's aides, flung themselves on the Sontaran troopers, snapping and rending with savage jaws. The Sentarrii had once been warriors too. More Sentarrii flooded in from the Inner Temple to join the fight. They fought with a dreadful ravening ferocity that chilled the blood. Most of the troopers were literally ripped apart. The survivors panicked and fled into the lush tropical garden. A ma.s.s of dark shapes moved in the green foliage.

The Harrubtii were waiting.

As the terrified troopers ran through the dense green foliage, the Harrubtii pounced, pulling them down, one by one.

Kurt made a dive for the stack of blasters, tossing weapons to Chris, Roz and Lisa.

'Back to the ship!' he yelled.

The Doctor grabbed Bernice's hand. 'When I say run run!'

Fighting their way through the carnage, sliding on the blood-slippery Temple floor, they fled into the tropical garden.

Lisa and Kurt ran ahead, Roz and Chris formed a rearguard.

They forced their way through the fringe of the battle, shooting down anything, Sontaran or Harrubtii, in their way.

Lisa saw one of the Harrubtii spring onto the back of a Sontaran trooper, search for a weak point and plunge its long spike deep into the probic vent. The trooper screamed and fell.

'Works even better than a screwdriver,' yelled Kurt.

They reached the ship at last, ran up the ramp and through the open airlock door. Lisa ran to the door controls.

A gentle voice said, 'Wait!'

A slender fair-haired young man stood in the doorway, covering them with a blaster.

'We are sorry,' he said. 'Now you must all die.'

'Who the h.e.l.l are you?' said Lisa.

'It's the Rutan,' whispered Roz. 'He's changed back.'

Chris couldn't believe such ingrat.i.tude.

'The Doctor saved you! Saved all your people.'

'He interfered in our plans. The wormhole can be reestablished, the escape route restored.'

'I a.s.sure you that's quite impossible,' said the Doctor.

'Perhaps so,' said the young man. 'But you know too much about us and our secrets. It is best for the Rutan that you die.'

Another shape appeared in the doorway behind the young man. It was Steg, blaster in hand.

The young man raised his blaster to shoot the Doctor.

'No!' shouted Lisa.

She raised her blaster, the young man swung round to shoot her first instead and Steg blasted him at point-blank range.

The Rutan blurred, collapsing in a gelatinous ma.s.s just as Lisa fired. Her blast pa.s.sed over the dying Rutan and into Steg.

He staggered back against the corridor wall and slid slowly to the ground, the blaster falling from his hand.

The Doctor looked down at him. 'It seems that I must thank you, Commander Steg.'

'No need, Doctor,' said Steg weakly. 'I came for my vengeance. As it happened, I could kill you or the Rutan. I chose the Rutan.'

Lisa knelt beside him. 'You saved my life again.'

Steg looked up at her. The thin Sontaran mouth twitched in an attempt at a smile. 'And you took mine.'

'It was an accident.'

'I have saved you twice, and you have killed me twice,'

said Steg. 'It...hardly...seems...fair.'

His head fell back.

Kurt turned to the others. 'Chuck the bodies out and let's blast off before any more of those jumbo beetles turn up.'

'No,' said Lisa. She pointed to the remains of the Rutan.

'You can get a bucket of water and swill that up, but Steg stays. We'll find a way of getting him back to his own people.

If they don't want him, I'll bury him myself.'

Kurt looked at her for a moment, and then smiled.

'Just as you like. Bury him by all means. At least that way we'll be sure the old b.u.g.g.e.r's really dead this time.'

Kurt dragged Steg's body away. Lisa sealed the airlock door and she and the Doctor headed for the control room.