He swallowed and licked his lips.

Jamie bit off a tiny piece and chewed tentatively. 'I hope I'll no need to do that: it tastes like old candles,' he grimaced, tossing the remainder to Kully.

Rousing himself, Jamie went across to the periscope, grasped the handles and pushed upwards. It slid quite freely, despite emitting a nasty sc.r.a.ping sound 'Let's see how the land Iies..' he muttered, peering into the binocular viewer. For while he was silent, twisting the tube slowly from side to side, then he turned.

Kully stopped chewing and stared at him.

'We've got visitors...' Jamie said. 'Lots of them.'

'Quark, order cancelled. Toba, what is the meaning of this?'

Zoe cried out in grat.i.tude and relief as Rago's powerful voice suddenly rang around the control centre.

Hissing with frustration, Toba spun round to face his leader as he emerged from the elevator followed by his escort.

Rago stared down at Balan's suit, at the cowering figures of Kando and Teel, and finally turned to his sullen subordinate. 'Explain, Probationer Toba' he snapped.

The Doctor mopped his glistening face and squeezed Zoe's cold hand gratefully. 'That was a trifle near the mark...' he whispered wryly.

Toba brazened things out as best he could. 'We were attacked, Navigator Rago. A Quark was destroyed, another damaged. In the emergency I decided to...'

'Emergency? Rago sneered. 'A handful of primitives manage to incapacitate a Quark and you interrupt vital projects to waste time and valuable power chasing them all over the Island?'

Toba creaked forward a few paces: 'I decided to hold an inquiry, Navigator...'

Rago turned impatiently and frowned dangerously at the bore-project display. 'Is drilling complete?'

'All four perimeter bores are completed,' said Toba hurriedly.

'And the centre target?'

Toba hesitated uncomfortably. 'A minor delay... caused by strata deviations.'

Rago leaned closer. 'The only deviations have occurred in your behaviour, Tuba. Quark power reserves approach minimal levels and drilling is incomplete, yet you fritter precious resources in fruitless chases and in killing insignificant aliens.'

Toba was aware of the Doctor's contemptuous stare boring into his back. 'I considered it my duty...' he protested.

'Your duty is to complete the project according to schedule,' Rago thundered. 'Have the rockets been installed at the perimeter targets?'

The Doctor's face lit up with profound interest and antic.i.p.ation and he edged surrept.i.tiously closer to gain a better view of the project display across the vast chamber.

'Not yet,' Toba admitted after an embarra.s.sed pause.

'Do it at once,' Rago ordered. 'Is the seeding trigger approaching criticality?'

There has not been sufficient time to determine.'

'Time?' Rago boomed, the rims of his eyes burning like red-hot rings. 'Toba, if you have jeopardised this most vital stage of our mission by your obsessive irresponsibility, then you will remain here on Dulkis and perish with the weaker primitives.'

The Doctor observed intently as Toba hurried across to the central dais and opened a heavily armoured circular panel near the one he and Zoe had examined earlier. A soft pink glow spread over Toba's body as he withdrew a large opaque object resembling an ostrich egg, encased within a kind of gla.s.s sh.e.l.l with short blunt spikes protruding in all directions. The Probationer peered at each protrusion in turn, the glow transforming his features into a caricature carnival mask.

'Report!' Rago rapped impatiently.

'The seeding trigger approaches criticality minus gamma.'

Toba carefully replaced the device and closed the thick panel.

Zoe glanced at the Doctor. He was uttering silently to himself and nodding knowingly as he watched Toba's every move.

'Minus gamma. Then there is not a moment to lose, Toba,' Rago warned urgently. 'The centre bore must be completed and projectiles will he inserted in the perimeter targets immediately. Understood?'

'Command accepted,' Toba promptly acknowledged.

Rago strode across to the Quark control unit and pa.s.sed his enormous hand over a sequence of coloured keys. 'The search is cancelled. All Quarks to position at drilling stations and conserve power until further instructions.' he ordered. Then he turned back to his suhordivatc 'I shall communicate with Fleet Leader regarding the exploitation potential of the primitives. Meanwhile, keep them under constant supervision.'

Ordering the two Quarks to follow with the four surviving prisoners, Toba strode towards the elevator.

'Toba.'

The Probationer stopped and waited.

'This your final chance. Do not waste it.'

As the captives were prodded into motion by the Quarks, the Doctor glanced sideways at Zoe. 'Speaking of chances,' he muttered, 'from now on we must be sure not to waste any of ours.'

For some time the a.s.sembled Quarks had remained motionless and silent outside the ruin, like a plantation of dwarf mechanical trees waiting for some unwary bird to light among them. Jamie peered apprehensively at them through the periscope, while Kully lay on a bunk, nervously devouring the emergency rations out of the locker. The tension was almost tangible, like the closeness in the air before a thunderstorm.

Suddenly Jamie whooped with delight. 'More visitors, Kully!' he exclaimed, as the Doctor, Zoe, Kando and Teel trudged into view.

Kully elbowed him aside. 'Balan isn't with them,' he muttered anxiously, panning the periscope. Then he groaned.

'More Quarks?' Jamie eagerly siezed the viewer again, but he too groaned as he watched Toba arrive and start supervising some of the Quarks around the rig. 'We've got to get them in here with us. We canna just leave them up there...' he said, focusing on the Doctor and Zoe.

'Here we go again,' Kully sighed, clutching head in despair.

The young Highlander grinned mischievously and glanced quickly round the bleak concrete shelter. His eyes lit on the plastic sheeting covering the bunks. He whipped a gleaming dirk out of its sheath inside his sock and rapidly slit the sheeting free from one of the mattresses.

Kully watched in baffled silence as he cut a long narrow strip from one side.

'Now listen carefully, Kully,' Jamie said firmly, 'this is what we'll do...'

Guarded by a single Quark and huddled some distance from the drilling apparatus, the Doctor and the others covered their ears and averted their faces as the rig began to whine and throb and an intense beam of light flashed down the barrel into the target hole. As the ground vibrated and the whole area shimmered in the hot searing glare, the Doctor attempted to squint under his thick dark eyebrows to observe the awesome procedure.

Zoe put her mouth close to his ear. 'Any idea what they're looking for?' she shouted.

The Doctor forced his blinking watering eyes to stay at least partially open for a few more seconds. Then he turned to her. 'Oh, I don't think they intend to take anything out out of the hole, Zoe,' he yelled back. 'More likely they're going to drop something of the hole, Zoe,' he yelled back. 'More likely they're going to drop something in in.'

'But what?'

Before the Doctor could reply, he caught a glimpse of someone moving among the debris up by the ruin, behind their Quark sentry. 'Oh dear me... oh no...' he muterred, as Jamie emerged crouching low and dropped onto his stomach behind a low ridge of sand.

The attention of Toba and of the Quarks was totally absorbed in the screaming and throbbing drill, as Jamie starred wriggling his way towards the unsuspecting robot.

With his back to the rig, the Doctor was able to watch in anxious fascination as Jamie knelt up behind the Quark, reached into his shirt and unrolled the thin plastic strip, Reaching forward, Jamie carefully wound the strong material round and round the robot's thick, concertina legs, binding them tightly together.

The reckless lad froze as the Quark's antennae waggled and flickered and its domed head stirred suspiciously.

Then the robot suddenly shifted slightly and its rectangular foot came down, trapping Jamie's hand underneath. Thrusting the end of the plastic strip into his mouth, Jamie stifled his agony.

Promptly the Doctor stepped forward. 'Excuse me, sir!'

he cried.

The sparking robot immediately unfolded its probes and went to advance on the Doctor, but as it tried to take a step it overbalanced and its bulky body pitched forward into the sand.

At that same moment, Kully scampered out from behind the ruin and enveloped the Quark's antennae in the plastic sheet, completely depriving it of its senses.

Blowing frantically on his throbbing hand, Jennie leaped up and, while Kully hurriedly shepherded the astonished prisoners safely into the ruin, he dragged a heavy beam from some nearby wreckage and heaved it on top of the struggling robot.

The disabled Quark started to emit a piercing distress signal which at first was inaudible against the howl of the drilling rig, but eventually Toba heard it.

Ordering operations to cease, Toba scanned the area in a frenzy. 'A Quark has been attacked and the specimens have escaped...' he screamed as the glare and the noise of the apparatus subsided. Striding towards the ruin, Toba hurled the beam aside and ripped the sheet off the stricken Quark, which began rolling about on its back like a mechanical beetle.

'Quark, where are the specimens?' Toba demanded.

'Sensors temporarily inoperable. No data recorded,'

bleated the robot pathetically.

Toba swung round hysterically. 'Quarks, search. Search and destroy...' he shrieked, starting to clamber over the wreckage around the ruined museum, kicking and hurling debris in all directions.

'Command cancelled!' Rago's voice sliced like a blade through the hot muggy air.

Toba lurched to a halt, his huge limbs jerking spasmodically.

'Why has drilling been interrupted yet again?' Rago demanded icily, approaching between the a.s.sembled Quarks.

Toba mumbled an explanation.

Rago surveyed the silent rig. 'Probationer, if you cannot perform the tasks a.s.signed to you here, you will never gain full Dominator status,' he rasped. 'Complete the bore.'

With as much dignity as he could muster, Toba clambered back onto the sand and strode back to the rig.

'The primitives will not escape unpunished,' Rago added with condescending generosity, as Toba ordered the Quarks by the rig to reconnect power. 'Fleet Leader confirms that Dulcians are totally unsuitable for our projects. Therefore they will die with their planet.'

Toba's eyes flashed with malignant satisfaction. 'Then the sooner we complete operations the better.'

'Exactly. I shall now supervise the positioning of the projectiles at the perimeter targets. Inform me when the centre bore is prepared for the seeding trigger.' Rago commanded a detachment of Quarks to accompany him and then strode rapidly away across the dunes.

Jamie had only just had time to squeeze himself through the hatch before the frenzied Toba clambered onto the wreckage above the open trap-door. In the shelter below, the six fugitives had then waited in total silence, scarcely daring even to breathe until the two Dominators moved away. Then at last Jamie had carefully lowered the heavy trap and jumped down to on the others.

'That was extremely rash of you, Jamie,' the Doctor scolded him, smiling appreciatively, 'those Quarks can be appallingly dangerous.'

'Och, they're nae so terrible,' Jamie grinned, giving Zoe an affectionate hug.

Kulls turned from the periscope. 'Where's Balan?' he asked.

Gently, Kando explained what had happened.

'You did all you could, Kully,' Teel murmured, nursing his bruised ribs. 'Thanks to you and Jamie, the rest of us are safe.'

'I'm not so sure about that,' Jamie told him. 'I just heard those Dominators saying that the Dulcians are no use to them.'

Kando smiled innocently. 'Then they will leave us in peace now.'

Jamie glanced at the Doctor and Zoe in embarra.s.sment.

Then he turned to the three Dulcians. 'They said that you would all die... with your planet,' he mumbled helplessly.

Kully peered back into the periscope. 'They can't destroy Dulkis...' he protested indignantly.

Just then the shelter began to vibrate as Toba's unit resumed drilling outside.

The Doctor coughed and cleared his throat. 'I'm afraid they can. I believe they intend to use your planet as fuel for their fleet.'

There was a long, shocked silence. The Doctor shrugged, smiled bleakly and then examined his fingernails minutely. 'I'm most terribly sorry.'

Then Zoe stuck her chin out. 'But Doctor, you decided that their saucer uses atomic power,' she objected.

'There are no suitable radioactive minerals in this hemisphere,' Kando reminded him.

The Doctor waved his arms impatiently. 'No, no, no, there is no reactor in the saucer, only a radiation acc.u.mulator and converter system.'