'But it's in the wrong place,' protested the Doctor.

Glitz shrugged. 'Only by a couple of light years.'

'That's why the lost expedition missed it,' said Dibber.

'What lost expedition?'

'Andromeda bunged off these robots in a relief s.h.i.+p'

'Don't prattle Dibber,' snapped Glitz. 'All that was a long time ago.'

Balazar cleared his throat. 'The word "Earth" is mentioned many times by that great writer HM Stationery Office.'

As no-one quite knew what to say to this, there was an awkward silence, finally broken by a shattering crash as the Service Robot smashed straight through the wall of the hut, showering rubble everywhere.

'I thought we'd seen the last of him as well,' said Dibber.

The robot stood swinging to and for as if uncertain what to do next.

'Shut up Dibber,' whispered Glitz, ducking behind his burly colleague for shelter. 'Stand in front of me where I can keep an eye on you.'

'Keep calm and stay still everyone,' said the Doctor quietly. 'It's looking for me, but I think it's still confused.'

Balazar and Broken Tooth were a little behind the Robot. They managed to slip through the open gap without being seen, but suddenly the robot got a fix on the Doctor and began advancing towards him.

'Can't you shake its hand or something?' suggested Glitz.

The Doctor stepped boldly forward. 'How do you do? I am known as the Doctor.'

He reached out and grasped an arm-like protrusion on the robot's casing - and received a shock that threw him clear across the hut.

Advancing on its victim, the robot extruded a number of steely, rope-like filaments. They whipped around the Doctor and dragged him towards the robot, las.h.i.+ng him to its casing in a sort of metallic spider's web.

Its victim firmly secured, the robot turned and trundled through the gap in the shattered wall.

'Now's our chance, Dibber,' said Glitz.

'We've got to help the Doctor,' screamed Peri.

'He'll be all right,' said Glitz soothingly. 'He's in good hands! Come on!'

'No!' protested Peri, but Glitz and Dibber dragged her away between them.

For the second time, Broken Tooth had the unhappy duty of telling Queen Katryca that she had lost her prisoners.

'Escaped? Again? I told you to guard them!'

'The Immortal came and took them,' said Balazar.

Katryca stared unbelievingly at him.

'We both saw him,' said Broken Tooth. 'He walked through the wall!'

Katryca leaped to her feet. 'Get the guns!' she ordered.

As the Service Robot moved away from the village, Drathro studied the monitor, brooding over the implications of what he had seen.

'Habitations! Only man makes habitations. All life on this planet perished in the fire. If men now live on the surface, they must have come from my biosphere. From here, underground...'

'How could that be?' said Humker, shocked.

'It is forbidden,' said Tandrell. 'All work-units obey your orders.' Drathro's deep voice was angry. 'Some must have escaped. They were helped to escape. That is what has happened.'

'They are not important,' said Humker.

'They are out of control' roared Drathro. 'Outside my plan.'

Tandrell nodded. 'They are outlaws.'

'Now my existence is threatened,' boomed Drathro.

'They have destroyed the source of my energy. We must take measures. Create a defensive system. Identify and destroy the traitors!'

Drathro was becoming paranoid.

In the Courtroom, the Doctor rose in indignation. 'All this is irrelevant and hypothetical.'

'Background testimony,' snapped the Valeyard.

'What possible value does the... farmyard here think there is in listening to a half-incapacitated robot, and a couple of diminuitive nitwits?'

'You are allowing your disrespect to show again, Doctor,' said the Inquisitor icily.

'I'm sorry, My Lady. But the question still stands.'

'The Valeyard has the right to include any evidence he considers relevant - provided he can justify its inclusion.'

'But surely,' said the Doctor, 'any record relating to persons not in my presence must be sheer conjecture?'

The Valeyard rose. 'The accused is clearly ignorant of the latest methods of surveillance, My Lady.'

The Inquisitor turned towards the Doctor. 'This evidence is taken from the Matrix - a knowledge bank fed constantly by the experiences of all Time Lords, wherever they may be.'

'Yes, yes, yes,' said the Doctor impatiently. 'I know that.

My whole point is - I'm not!'

She stared at him in exasperation. 'Not what?'

'Not present,' said the Doctor. 'Not part of the scenes being presented by the sc.r.a.pyard, sorry, sorry, force of habit, the Valeyard here.'

The Valeyard gave a superior smile. 'Ah but Doctor, the experiences of third parties can also be monitored and accessed if needed - as long as they are in the collection range of a TARDIS.'

The Doctor looked nonplussed. 'Indeed? But my TARDIS is an old model. Are you telling me it's been bugged - without my knowledge?'

'Bugged?' The Inquisitor was baffled.

'A reference, apparently, to the new surveillance system,' explained the Valeyard. 'The Doctor is using an Earth term.'

The Inquisitor was becoming impatient. 'I think we are wasting time on an unimportant issue. Continue, Valeyard.'

The Robot trundled through the forest, the Doctor lashed to its casing by a steel coc.o.o.n.

A large party of warriors appeared in the woods ahead.

It was led by Broken Tooth, and by Queen Katryca herself.

Both carried laser rifles. Many of the others also carried guns, weapons taken from certain unfortunate Star Travellers in years gone by.

'Stop Immortal!' roared Katryca.

Like the rest of her people, she had a.s.sumed that the robot that had attacked them was the Immortal of whom escapees from the underground had spoken - not realizing that the real Immortal was a far more formidable proposition.

The Service Robot ignored her.

Raising her rifle, Katryca opened fire.

Broken Tooth followed, and a ragged volley of laser-bolts and projectiles hummed around the robot. Some of them actually hit it, more by luck than skill.

The robot staggered, then lurched forward with its living cargo as the tribesmen fired again and again. From a nearby hillock Dibber and Glitz watched with detached interest while Peri, held firmly between them, looked on in agonized concern.

'They'll kill the Doctor,' she shrieked.

'We've all got to go some time,' said Glitz philosophically.

'You're all heart,' said Peri bitterly.

'The supreme sacrifice - and all for us,' said Glitz admiringly. 'What a person. If I have time I shall compose the eulogy for his funeral.'

There was another ragged volley and another. Smoke streaked from the robot's casing. It lurched forwards a few more yards, and then toppled slowly over.

Drathro and his a.s.sistants watched the battle on the monitor - until, that is, the picture lurched dizzily and the screen went blank.

The scenes they had witnessed provided fresh fuel for Drathro's paranoid fears. 'They have guns. From where?'

'Guns can be manufactured,' said Humker.

'Indeed,' said Tandrell. 'But their manufacture requires advanced technology.'

'The fact that they have guns means they also have advanced technology.'

'False reasoning, Humker,' said Tandrell. 'They are savages. Therefore their guns must have been supplied from without.'

Humker glanced at the blank screen. 'The Service Robot has ceased to function.'

'On our present data, that is the logical conclusion,'

agreed Tandrell.

'It is obvious. It has ceased transmitting signals.'

'The Doctor is from Gallifrey,' rumbled Drathro in his deep mechanical-sounding tones. 'He has been sent to recover the secrets left by the Sleepers. To do that, he has armed the outlaws. He intends to foment rebellion against my authority.'

Tandrell put his head close to Humker's and whispered, 'And with nothing left here but the power from a few backup storage cells, he's quite likely to succeed.'

'Then what will happen to us?' whispered Humker.

Tandrell looked at him. 'I dread to think...'

For some time Merdeen had suspected he was being followed. He ducked suddenly into an alcove and waited.

Grell came along the corridor, crossbow in hand.

Drawing his own weapon, Merdeen stepped forward to confront him. 'Are you following me?'

'Like you I'm looking for a lost man. It occurred to me that it might prove more productive if we worked as a team.'

Merdeen said suspiciously, 'What makes you think the Doctor and Balazar will be together?'

'Events,' said Grell mysteriously.

'Meaning?'

'I don't think the Immortal's orders are always carried out,' said Grell. 'Especially when it comes to Culling.'

'I always supervise the Culls myself,' said Merdeen calmly.

'I know.'

'Then what are you suggesting, Grell?'