'What secret?'

'I don't know the files were largely destroyed. As far as I could gather, the Sontarans had stumbled on the secret's existence by accident. But they were confident that they could use it to achieve a final, crushing victory. They also feared that an agent of yours, someone they called Karne, knew that they knew about the secret, and would try to warn you.'

(It's hopelessly vague, but it's all I've got to go on until Roz and Cwej or Bernice come up with something.) Roz and Cwej or Bernice come up with something.) Another silence. Another silence.

'Why do you tell us this?'

'To help you. Whatever this precious secret of yours is, the Sontarans are on its trail. You need to protect yourself.'

'Why should you wish to help us?'

Now it was the Doctor's turn to pause. He decided to be openly Machiavellian to fall back on absolute honesty.

'Because you are the only force that can contain the Sontarans. If you are ever totally defeated, they'll turn their attentions to the rest of the galaxy.'

There was another long silence. At last the icy voice said, 'What you suggest is impossible. No such secret exists. The Sontarans can never defeat us. It is we who will win.'

'Please, you must listen '

The hovering shape of the Rutan pulsated with light.

'Go, Doctor. Whatever your motives, you have tried to serve our cause. We shall allow this to cancel out our death on Fang Rock. We shall allow you to live. Do not interfere further in our affairs. If you do, you will die.'

The Rutan floated back up the ramp and vanished inside the ship. The ramp retracted, the aperture closed and the Rutan ship sank slowly beneath the icy waves.

The Doctor turned and went back inside the TARDIS, his mind full of 'if onlys'.

If only Roz and Cwej had succeeded in finding Karne, he could have used the Rutan spy to confirm the truth of his story.

If only Bernice had found some clue as to the great secret, he could use the information to force the Rutans to be more frank with him.

But they hadn't, not yet, and the Doctor had decided it was worth trying to convince the Rutans of their danger on his own. There was no telling if he'd done any good. Still it had been worth a try and at least he was still alive.

He wondered how Roz and Chris and Bernice were getting on. Surely he would hear from them soon.

Provided, of course, that they they were still alive. were still alive.

The Doctor set the controls for dematerialization, and the time-rotor began its steady rise and fall. Hands spread flat on the console, eyes staring blankly ahead through s.p.a.ce and time, the Doctor pondered his next move.

Inside the Rutan ship, in a crystal chamber with gently glowing translucent walls, the Rutan captain held counsel with their crew or rather, with the other embodied aspects of their Rutan self.

Close together in the familiar atmosphere of the ship their minds were as one, the flashing thoughts accessible to all.

'Does the Doctor know the secret?'

'That is not possible.'

'If he does, he must die.'

Then the captain. 'He does not know the secret. He knows only that it exists. We believe he spoke the truth.'

There was a silence, heavy with concentrated thought.

'Perhaps we should close the Way.'

'The Way has served us as safeguard for generations. We need it still.'

'An a.s.sociate of the Doctor is on Sentarion. She seeks to discover the secret.'

'She will find nothing. Our servants will deal with her.'

'The Doctor is cunning. He may still discover the secret of the Gateway. He may lead the Sontarans to it.'

'If there is danger of this, the Doctor must die.'

'Safer to kill him now.'

'No. He may yet be of use to us. We will observe, and wait.'

'He spoke of Karne.'

'Karne died long ago.'

The captain's mind again. 'We did not sense his going from us.'

'Karne lived too long amongst aliens as an alien. His links with us were weakened, his mind corrupted.'

'Karne endangered his Rutan soul to serve our cause. He was the greatest of all our spies.'

'Karne is dead.'

A surge of hope flooded the Rutan mind. 'No. We believe that the Doctor spoke truth. Karne lives!'

On the Sontaran War Wheel, a planning conference was about to begin. It was to be presided over by Admiral Sarg, commander of the Special Expeditionary Force.

To be present at the conference, to be on board the War Wheel at all, was a signal honour.

This was the most important military expedition in Sontaran history. The force that was to defeat the Rutans for ever.

Commander Steg looked round the dark and gloomy conference room. It was a ma.s.sive hexagonal chamber, stark, metallic and functional.

High-ranking Sontaran officers, each accompanied by staff and aides, sat straight-backed on metal benches, grouped in a semicircle around Admiral Sarg's command chair.

Despite his comparatively low rank, Steg occupied a place of honour in the front row. He was acting as the Admiral's aide. For his own aide he had a certain Lieutenant Vorn a mixed blessing since Vorn's intelligence failed to match his undoubted enthusiasm.

Vorn, thought Steg cynically, was lucky to be here. He owed his place on the expedition to his membership of the influential Gunnar Clan. Such factors were supposed to be of no account in Sontaran society, but clan influence carried weight. It always had, and it always would.

Not, reflected Steg, that he had any right to be critical. He was lucky to be here himself after Jekkar.

After years of glorious and successful service, Commander Steg had been placed in command of the force sent to take over a primitive agricultural planet on the far edge of Sontaran s.p.a.ce. The planet, it was felt, might make a useful advanced command post, one of the wide ring of disposable buffer planets surrounding the Sontaran home world.

It had begun as a model operation. Steg's main force had captured the s.p.a.ceport and its adjoining town, while smaller forces took over the handful of scattered human colonies.

The conquest of the planet had gone according to plan.

Nothing else had.

The human colonists presented no problem. A few exemplary executions had soon ensured their co-operation.

Trouble came from a totally unexpected source.

According to the information provided by Intelligence, the planet's nearest approach to an intelligent life-form was a primitive species of giant anthropoids called Jekkari. They were timid, non-technological and presented no danger whatsoever.

As Steg had pointed out in a series of increasingly acrimonious complaints to Intelligence, he had been seriously misinformed about the Jekkari.

Far from being timid, they were cunning and ruthless guerrilla fighters. They raided Sontaran bases, ambushed land convoys and brought the occupation of the planet to a grinding halt.

Their attack methods, if primitive, were ruthlessly effective. Falling trees and hidden mud-pits disposed of Sontaran ground-cars and their occupants. And if the Jekkari had no technology of their own, they proved appallingly capable of handling stolen Sontaran weapons. It was an uncomfortable experience, Steg discovered, being bombarded in your besieged base by your own stolen field-cannon.

After every raid, the Jekkari disappeared into their endless forests. The Sontaran patrols that went in after them never came out again. As soldiers do, Steg began to get the feel of the mind that opposed him. He was convinced that the Jekkari were being led led by a guerrilla general of genius. by a guerrilla general of genius.

He a.s.sumed at first that the Jekkari themselves had thrown up this unknown leader. But rumours filtered back of someone human, or humanoid, fighting with the Jekkari guerrillas.

Interrogated colonists came up with the matching description of an eccentric wandering scholar called Smith who had been studying the indigenous life-forms.

Steg remembered a couple of insignificant fugitives, captured on the first night of the invasion. He checked up on the details of their execution, and discovered that it had never taken place. They had escaped. He had held the enemy in his grip and lost him.

The guerrilla attacks went on. Steg fought back with savage efficiency, but his resources were limited and he was overstretched. His invasion force decimated, he sent for reinforcements.

Reinforcements were refused.

Instead it was decided that perhaps, after all, the planet was too far from the home world to make an effective advance base. Another would be found. The High Command ordered not a retreat the word did not exist in Sontaran military vocabulary but a strategic redeployment of resources.

In practice, this meant that Steg blasted off with his few surviving troopers in his few still-unsabotaged s.p.a.ceships. It was the smallest of incidents in the unending Sontaran-Rutan war, but it was a blemish on his record all the same.

For this reason Steg had fought desperately to be included on this expedition. He owed his place to the fact that Admiral Sarg still had faith in him. They had served together when Steg was a young lieutenant, and Sarg still a commander.

Something of a link, almost a friendship, had grown up between the future admiral and his lieutenant. Perhaps it was because they shared, unlike most Sontarans, a dangerously individual cast of mind.

Commander Steg's reflections were interrupted by the arrival of Admiral Sarg. The ranks of Sontaran officers rose as one, arms across their chests in salute.

Admiral Sarg waved them to be seated and sank, a little stiffly, into his command chair. Steg studied his old commander keenly. Sarg's skull-wrinkles had deepened with age, and his eyebrow-bristles and vestigial Sontaran beard were now pure white. But the fierce red eyes that swept round the group of high-ranking officers were alive as ever.

The admiral's deep, rasping voice rolled around the conference chamber. 'This expedition, as you know, has been a long time in preparation. Some of you at least may be surprised by the suddenness with which it was actually mounted.'

Most of the Sontaran officers present stared blankly at him.

It would not have occurred to them to question their orders.

They simply obeyed. Up to a certain point this is an excellent att.i.tude in a soldier. But in the highest ranks, where independent thought is not only desirable but necessary, it can be a positive disadvantage. Even the Sontarans were slowly coming to realize this. It accounted for the unofficial tolerance towards such mavericks as Admiral Sarg.

Steg had noticed the discrepancy to which the admiral referred. It had long been rumoured that the High Command were preparing some devastating stroke against the Rutan enemy, some hammer-blow that would end the war altogether.

Yet the expedition itself had been mounted in a kind of scrambling haste. The War Wheel had been a.s.sembled, its crew of troopers and officers recruited at top speed, as if some last-minute crisis had occurred.

'For security reasons, what I can tell you is limited,' Sarg continued. 'But you must know this. For some time we have suspected the existence of a secret weakness in the Rutan defences. Our task has been to find it and exploit it. That task is almost almost complete. However, there is one other important factor. It is vital that we know the Rutan secret but it is equally vital that they do not know that we know.' complete. However, there is one other important factor. It is vital that we know the Rutan secret but it is equally vital that they do not know that we know.'

Admiral Sarg surveyed the largely blank faces of his officers and sighed. 'Let me put it another way. You are attacking a heavily defended enemy base. Word reaches you that a door has been left open. You plan to find that door and press home your attack. But what happens if, before before you find the door, your enemy discovers that you are looking for it?' you find the door, your enemy discovers that you are looking for it?'

No one answered, and Sarg snapped, 'Commander Steg?'

'The enemy find the door themselves and shut it.'

'Precisely. They shut the door!' Sarg slammed a three-digited hand on the arm of his chair. 'Now listen carefully this data will not be repeated. As you all know, amongst the many disgusting characteristics of our Rutan enemy is the ability to mimic the appearance of other life-forms. They can even take on the form of Sontarans. One particularly skilful Rutan spy a.s.sumed the ident.i.ty of a Sontaran officer called Karne, and maintained it for a considerable period of time.'

A shocked murmur spread through the conference chamber, and one or two officers began glaring suspiciously around them.

'Do not concern yourselves,' said Sarg drily. 'You will recall that you were subjected to an extensive scanning process before boarding. I can a.s.sure you that no Sontaran officer in this chamber is really a Rutan.'

Admiral Sarg's thin lipless mouth twitched at the corner.

He glanced at Steg and saw an answering twitch. Everyone else looked appalled at the very idea.

'Until recently we believed this false Karne to be dead,'

Sarg went on. 'Reports have now reached us that he lives.

Worse still, it seems possible that he has learned that we suspect the Rutan secret, and is returning to his home planet to warn them. If he succeeds, our mission will fail before it has begun.'

He glared around the room. 'Priority One Karne must be found and killed before he can deliver his warning. Our agents are on his track. As soon as he can be located, we shall destroy him.'

An angry growl of agreement filled the conference chamber.