Narrowly missing Balan, the missile struck one of the Quarks squarely on its vertical antenna. Instantly, both Quarks disconnected themselves from the rig and swung round, scanning the dunes in a frenzy of bleating. Balan flung himself headlong in a panic, and lay still.

Chuckling with delight, Kully dug furiously with his finger, and prised up another rock. 'Do it again.. do it again...' he begged, pa.s.sing it to the crouching Jamie.

Jumping up, Jamie repeated the attack. 'Take that ye wee porridge pot!' he yelled as the second stone crashed onto the domed head of the same Quark.

The other Quark jerked round and fired its probes. A fountain of molten sand flew up into Jamie's face as he threw himself flat. Suddenly the cliff started to disintegrate around them as the two Quarks fired simultaneously, carving deep gouges out of the soft ridge.

'Time to go!' cried Jamie, scrambling up. But at that same moment there was a mighty roar and the whole cliff collapsed, hurling him helplessly down onto the dunes and leaving Kully scrabbling desperately halfway up the crumbling face in an avalanche of sand.

Picking himself up, Jamie raced towards a steep V-shaped gorge dividing the cliff at right angles nearby.

Sizzling spouts of sand soared all around him as he fled up the sloping cleft with both Quarks tramping rapidly in pursuit.

Meanwhile Kully had managed to scramble back to the clifftop, tripping. as he went, over the length of pipe.

Seizing it, he stooped low and scampered towards some large spherical boulders precariously perched on the edge of the gorge. Reaching them, he saw Jamie below him, running for his life as the gorge exploded around him.

Kneeling behind the biggest stone, Kully inserted the pipe at an angle and heaved. To his delight, the boulder stirred and settled back again. Tingling with excitement, Kully waited until the two Quarks were almost exactly beneath him and then threw all his weight against the pipe.

Gradually the huge stone moved forward. Then it tipped over the lip of the gorge and rolled faster and faster, bouncing down the steep slope in gigantic arching leaps.

Recklessly Kully stood silhouetted against the sky yelling in triumph as the boulder flattened one Quark completely and knocked the other on its side in a cascade of sparks.

'Mac... Cr.i.m.m.i.n.g's for ever. Death to the Redcoats!'

Kully's victorious cry changed abruptly into a squawk of terror as the edge of the gorge gave was under him and he plunged over and over in a flailing of arms and legs, finally coming to rest next to the astounded Jamie in a hollow.

'Well...' he spluttered, spitting sand out of his mouth and blinking his watering eyes. 'Well, I'm with you now all right!'

A little way down the gorge, the damaged Quark was already whirring back into action. Levering itself upright again, it swung its glowing antennae wildly about like a bundle of fluorescent blades, seeking out its prey trapped in the dead-end of the valley.

8.

Clues The Council had been in session for hours. Director Sencx reclined in his chair, silent and pensive, only half listening to the interminable drone of the Councillors' deliberations.

The violent memory of the Quark attack in the survey module was burnt indelibly in their minds and they had still not recovered from the shock and disappointment of Chairman Tensa's advice.

There was a long silence. Suddenly the Director's face betrayed the deep and impotent anger surging through his being. 'It is our tragedy to do nothing. We are the prisoners of our own negative philosophy,' he declared. 'Little wonder that some of our youth like my own son are determined to rebel.'

'But why should the aliens intend as harm us?' asked Deputy Bovem for the thousandth time. 'No intelligent race would indulge in irrational purposeless violence...'

Scarcely were the words out of his mouth than the wall of the chamber parted to admit the huge lumbering figure of Rago, closely followed by his Quark escort. There was an awed and appalled silence while the Dominator flashed his emerald glare around the a.s.sembly.

'Who is in control here?' Rago rasped.

Scnex cleared his throat. 'I am the Director,' he replied calmly.

'If you would care to make an appointment...' Bovem began.

Rago turned on the Deputy, his boots and gloves creaking eerily. 'Listen and obey,' he commanded. 'I require information.'

Chairman Tensa strode forward. 'I must protest. Such discourtesy to the Council is tolerable!' he cried.

Rago stared at him incredulously. 'Protest?' he hissed.

'You defy me? You defy a Dominator?'

Tensa stood his ground. 'Our Director's rank demands respect,' he retorted.

'Demands... respect?' Rago echoed, his harsh voice brittle with mockery. 'Your leader is nothing to me. I respect only superior force.' He swung back to loom over Senex who had risen with great dignity. 'I command you to supply...'

'Sir, you would do better to request rather than command,' Tensa interrupted, forcing his way between Senex and the ma.s.sive alien.

'After all, your visit is not even on the Council Agenda; objected an aged Councillor.

Tensa opened his mouth to continue.

'Quark!' Rago rapped, stepping quickly back and pointing at Tensa's outraged face. 'Destroy.'

A ghost of a smile, chased by a look of sheer uncomprehending horror, flitted across Tensa's fine features. Before he could speak, the robot bleated its warning and then discharged a brief, devastating bolt of energy. Tensa's robe fluttered to the floor around the pulverised remains of his body. The Councillors recoiled and fell back in their chairs in stunned silence.

Rago towered over Sencx. 'I have no desire to repeat such action,' he stated tonelessly. 'Let it demonstrate that we Dominators are to be obeyed without question.'

Senex stared back at the alien, his eyes dulled with shock.

'You will place at our disposal the strongest of your species,' Rago instructed him.

After a long pause, Senex recovered his voice. 'You...

yon seek our a.s.sistance?' he said in a dreamlike monotone.

Rago smiled a bleak, humourless smile. 'a.s.sistance? I require slaves. Nothing more, nothing less,' he retorted.

Somehow Senex managed to talk through his numbed lips. 'Had you come to Dulkis in peace we should have done all in our power to a.s.sist you, but we cannot bow to...'

'What we require, we take,' Rago thundered dismissively. 'We control ten galaxies. Our mission is to colonise certain others. For this task our Quarks are needed, therefore we must replace their functions on our home planets.'

'With slaves,' Senex added flatly.

'Exactly. Those selected from your population will be fortunate. They will be saved.'

'Saved?' croaked Bovem. 'Saved from what?'

'Only the strongest are suitable,' Rago hissed, striding wards the wall and rounding on the cowering a.s.sembly.

'You will co-operate or perish. The choice is yours.' The wall opened and the alien and his robot disappeared. After a long time some of the Councillors ventured forward and knelt by the broken body in their midst.

'Can we not punish them?' the aged Councillor cried in a choking voice, wringing his gnarled hands incessantly.

Bovem glanced round at each member in turn. 'What did the alien mean... some of us would be saved?' he breathed. 'Saved from what?'

Sinking back into his chair, Senex shook his head and sighed. 'Perhaps from ourselves,' he murmured hopelessly.

'Perhaps from ourselves...'

When the Doctor and Zoe arrived back at the saucer with Toba, the control centre was humming with activity.

Quarks marched about, plugging themselves into computer terminals and systems displays as they performed the complex sequences of the drilling operation. Tuba began to stride up and down, bloated with self-importance and revelling in his temporary role of commander.

'Report progress to Fleet Leader,' he instructed a Quark.

'All perimeter bores completed. Central bore approaching optima...'

The Doctor stood in the shadows with Zoe, his hands plunged deep in his pockets, long furrows stretching each side of his nose. 'We must find out what they're drilling for,' he exclaimed.

'Fat chance with all these Quarks everywhere,' Zoe grimaced.

'Hmm. If only we could distract them somehow,' mused the Doctor, peering vainly about for inspiration.

At that moment, two symbols started flashing on the Quark control unit. Toba rushed over and thumped the panel with his giant fist. One of the symbols stopped flashing and remained 'Another Quark has been destroyed and a third has been damaged,' Toba raged.

'This could be just what we need,' the Doctor muttered, pulling Zoe further into the shadows. They watched the frenetic alien intently.

'Quarks follow!' screamed Toba.

Immediately the robots disconnected themselves and followed Toba out of the control centre in a sparking, chattering line. Soon Zoe and the Doctor were left quite alone.

'Who would destroy a Quark?' Zoe wondered.

The Doctor grinned broadly. 'I think I can guess!' he cried, rubbing his hands together gleefully.

'Jamie!' Zoe exclaimed after a momentary pause. 'So they did escape after all.'

'Alive and kicking by the sound of things,' the Doctor agreed. 'Good lads! We must make the most of our opportunity.' He scurried off round the huge circular chamber, peering closely at print-outs, displays, inspection panels and crystal switches, and muttering furiously to himself the whole time.

Zoe did her best to keep up with him. 'What exactly are we looking for?' she asked breathlessly.

'I want to find out what they feed this thing on,' replied the Doctor, darting into an elaborate a.s.sembly of flickering tubes.

Zoe trailed after him. 'Well, the Quarks seem to use ultrasonics, so presumably it's a fuel capable of producing random amplified fields and accelerated phases,' she suggested.

'Hmm, it must be quite powerful too,' added the Doctor, poking thoughtfully among the coloured fluorescent columns.

'Well, that's what I just said.. ' Zoe stopped and blushed, realising too late that she had been sent up. 'Look, if you don't want my help, Doctor...'

'Oh but I do, Zoe,' the Doctor a.s.sured her, backing carefully out of the ma.s.s of tubes and standing upright again. 'Now, my dear, where do you think the essential power source is lurking?'

Zoe walked around fora few seconds frowning with concentration. 'Well, if they use ultrasonics...'

'No, no, no...'cried the Doctor, 'more likely to be some form of particle acccicmtion.' He dropped to his knees and started to crawl round and round the central control dais, his nose to the deck like a bloodhound. Eventually he stopped, sniffed, crawled backwards a few metres, stopped, sniffed, crawled forwards a metre and finally stopped.

Then he tapped a small panel in the side of the dais.

'Here we are!' he cried. 'Just as I expected.' He tapped again and than listened. 'Or is it?' he demanded, kneeling up and staring enquiringly at Zoe.

She shrugged impatiently.

'Well, there's only one way to find out.' Taking a small penknife from his pocket, the Doctor began prising at the edge of the access panel, still muttering away. Suddenly the panel sprang free. Carefully the Doctor removed it and peered inside. He c.o.c.ked his head and listened. Then he sniffed a few times and to Zoe's astonishment, licked his finger and poked it into the opening for several seconds.

'Oh dear...' he sighed. 'Oh dear, oh dear, oh dear...' He clicked his tongue and shook his head.

'Whatever's the matter Doctor?'

Instead of answering, the Doctor pulled out a compact, tubular instrument, shook it, blew on it and then tied it to a long piece of string. Cautiously he lowered the gadget into the opening, paying out the string as it went.

Suddenly a series of sharp clicks emerged from the gadget. The Doctor frowned and nodded energetically. 'I thought so...' he murmured, paying out more string. The clicking increased dramatically as the Geiger counter registered radiation.

'Atomic reactor?' Zoe asked, craning over the Doctor's shoulder.

The Doctor stared down at the cl.u.s.ters of spherical vessels filling the entire area under the dais. 'No, my dear, nothing as crude as that,' he replied at last. He hauled the Geiger counter out of the trap and thoughtfully wrapped the string tightly round it. 'No. This is almost certainly a form of negative ma.s.s flux absorption system.'

Zoe's eyebrows shot up. 'A what?'

'A sort of radiation vacuum cleaner,' the Doctor explained. 'It would account for the sudden disappearance of radioactivity from the Island.'

You mean this thing sucked it all up?'

'In a manner of speaking, Zoe, yes.'

Zoe pondered a moment. 'Then what on earth are they drilling all those holes out there for?'

The Doctor tapped his nose with the coc.o.o.n of string. 'I wish I knew, my dear... I wish I knew...' he mumbled vacantly.