Balan turned gravely to the slim young man beside her.

'Teel?'

'Zero confirmed,' Teel announced in a puzzled voice. 'I do not understand it.'

Bolan glanced anxiously across at the three figures sagging limply against the observation port, their tongues hanging out and their eyes rolling. 'There must be an instrument malfunction,' he murmured. 'They had no protection at all. The count cannot be zero;'

'We cannot leave them in there much longer!' Kando warned him.

After a moment of agonised indecision, Balan leaned over and touched a switch. The airlock chamber door swung open and the three sweating, gasping victims stumbled out into the clinical and complex laboratory.

'What... what the divil are ye trying to do, ye Sa.s.senachs... cook us?' Jamie spluttered. 'Cos I'm no haggis...'

The Doctor restrained him as best he could and staggered angrily over towards Balan who backed away from him pointing a small Geiger counter at arm's length.

'All totally un...unnecessary,' the Doctor panted, brushing the instrument aside. 'There's not a trace of contamination on any of us.'

Calmly Balan checked the reading. 'Strange, is it not?

The whole island has been lethally radioactive for 172 annos,' he said in a cultured voice.

'Well, it isn't now!' Jamie snapped rudely, clutching his head.

'Of course it is,' Kando corrected him politely.

'I suggest that you check,' the Doctor advised Balan firmly.

'We have only just arrived here,' Teel explained. 'The annual environmental audit will he conducted during the next few days.'

The Doctor moved closer to Balan and addressed him with confidential urgency. 'I insist that you order a check immediately. It could be of the utmost importance.'

Balan stared impa.s.sively at the dapper stranger for a moment. Then he turned and nodded to Teel. The young Dulcian picked up the Geiger counter and his helmet, and hurried out.

'What is happening here?' Balan suddenly demanded, glancing at Zoe and Jamie. 'I was not aware that any other persons were permitted to work on the Island.'

'Neither was I,' bluffed the Doctor, smiling courteously.

'We were rather hoping that you might be able to enlighten us.'

Zoe stared at the formidable array of equipment around them.

'Why is the Island supposed to be so dangerous?' she asked, wincing from the dull headache her recent ordeal had given her.

Balan frowned in surprise. 'Everyone is aware of the atomic test...'

'But I thought you had abolished such research here on Dulkis,' the Doctor exclaimed.

Balan shook his head. 'You seem very poorly informed about your own planet.'

'That's because our own planet is...' Jamie clammed up as the Doctor kicked him sharply in the ankle. But it was too late.

The Doctor looked furious, but simply shrugged. 'As Jamie was about to reveal, we come from a different planet... indeed from a different time,' he admitted.

Balan seemed completely unmoved. 'Really? Not from Dulkis. I must record that in the bulletin,' he said. Then he smiled indulgently: 'That explains why you exposed yourselves to the dangers on the Island. No Dulcian would be so foolhardy.'

'Then what the divil are you you doing here?' Jamie demanded roughly, turning to Kando. doing here?' Jamie demanded roughly, turning to Kando.

She drew herself up with elegant pride. 'We are members of Educator Balan's university research group'

The Doctor intervened hastily. 'When I visited Dulkis before, it was a civilised and peaceful place,' he remarked gently.

Again Balan looked singularly unimpressed. 'This is not your first visit. I must note that in the bulletin.'

'But what has happened here?' the Doctor inquired impatiently. 'Why are you conducting atomic tests?'

Balan smiled and turned to Kando. 'The Seventh Council...' he prompted her.

There was a brief silence while Kando muttered parrot-fashion under her breath about fifth and sixth councils and the Doctor shuffled restlessly from foot to foot, nodding encouragement.

'... the Seventh Council under Director Ma.n.u.s initiated research into atomic energy, using this Island as a test site for the device, the results of which can be seen today...'

Kando recited tonelessly. 'Thereafter all such projects were prohibited. The Island is preserved as a museum and as a warning to future generations.'

'She's certainly done her homework!' Zoe remarked, with a sarcastic grimace at Jamie.

Oblivious, Balan beamed at his pupil approvingly.

Meanwhile the Doctor had wandered off around the laboratory, shoulders hunched, hands deep in pockets.

'Atomic weapons or no atomic weapons... that was quite a bang we heard,' he murmured. Then he stopped in his tracks, face to face with Balan. 'So what has happened to all that radiation?' he demanded. 'I do hope you don't suspect that its disappearance has got anything to do with us!'

As soon as Rago and Toba were out of sight, Kully emerged from his cramped niche among the debris and scurried over to look at the sticky black markings in the sand, not far from the wall of the museum. Then he noticed several sets of regular rectangular tracks and shuddered at the memory of the ruthless robots he had seen earlier.

A sudden movement behind him made him jerk round with a gasp. A tall faceless white figure was clambering over the wreckage towards the ruin. Springing up, Kully started to run as fast as his short plump legs would carry him, away towards the dunes.

'Kully... Kully!' rasped an echoing metallic voice. 'What are doing here?'

Kull stopped but dare not turn round. 'Who... who isthat?' he shouted, as heavy footfalls thumped up behind him.

'It is Teel. I am with the survey group.'

Kelly spun round, almost crying with relief as the suited figure ran up to him. He peered into the dark visor, but saw only his own terrified bulbous face reflecting back at him.

'Surely you remember me?' rasped the voice through the helmet speaker.

'Survey group!' Kelly gasped, gripping Teel's arm.

'Take me there. Quickly, take me there.'

'But what are you doing out here like that?' the voice demanded in astonishment.

Kully tugged frantically at the thick suit-sleeve. 'Don't argue, just take no there; he pleaded.

As Teel led the way swiftly hack to the survey module, Kully trotted along beside him endlessly jabbering about aliens and robots and giant wooden boxes, until Teel began to fear that either the frenzied Dulcian had lost his sanity or he was suffering from some kind of radiation sickness.

Meanwhile, back in the cool humming chamber of the survey module the Doctor was pacing agitatedly. 'But why should you think that we are responsible?' he objected.

Balan shrugged. 'It is possible that your craft... your TARDIS has attracted the radiation somehow and absorbed it,'; he speculated blandly.

'Nonsense. Quite out of the question,' the Doctor protested vehemently, running a critical eye over the module's instruments.

Zoe and Jamie were deep in conversation with Kando.

'Do s.p.a.cecraft often visit Dulk s?' Zoe wondered.

'I believe that yours is the first,' Kando replied.

Jamie looked baffled. 'Bell, ye dinna seem very surprised a see us.'

Kando frowned at the strange young man's curious speech. 'We Dulcians are taught to accept fact,' she explained. 'You are here that is fact. That you come from another planet I must accept as fact, since I have no evidence to prove otherwise.'

Jame stared mischievously at her, trying to think up some way to shock the serene young Dulcian.

Suddenly the airlock hissed open and Teel entered, removing his helmet. 'Not a trace of local radiation,' he announced. 'But look what I did find!' he added, ushering forward a dusty, rumpled figure covered in scratches.

'Kull y!' Balan exclaimed with a start. 'How do you come to be...?'

'Never mind that now,' Kully cried, ignoring the Doctor and his two companions and seizing the Educator by the arm. 'We must get back to the Capitol immediately.'

'Impossible,' Balan retorted. 'We have not even begun our survey for the annual audit.'

Kully stared at him wild-eyed. 'You'll all be wiped out here!' he cried.

Teel laughed uncomfortably. 'He claims to have seen aliens and killer robots and s.p.a.cecraft,' he explained.

Balan turned to the Doctor. 'You did not mention that you had brought robots.'

Before the Doctor could reply, Kully babbled on recklessly. 'Listen, Balan, I brought three citizens to the Island in my hovercraft. The robots killed them and destroyed the ship.'

Balan started to smile and then broke into a deep remnant laughter as he turned to the Doctor, Jamie and Zoe. 'Three citizens... I sec. Really Kully, you and your three friends here should at least have agreed on the same story.'

The Doctor looked fl.u.s.tered. 'I have never seen this person before in my life,' he protested, gesturing at Kully.

Balan turned gravely to the dishevelled Dulcian. 'Kully, you may be the son of our distinguished Director, but you had no right to bring these people here without authorisation,' he said coldly.

Kully stared in turn at the three strangers. 'These aren't my clients. I've never seen them before,' he retorted. Then he grabbed Balan's arm again. 'Listen, you old fool, there's no time to lose. Call up my father in the Capitol... at least he's not as senile as you are.'

Before the outraged Educator could find words to reply, the Doctor hurriedly intervened. 'You say that you saw a s.p.a.cecraft?' he asked Kully.

'I've already told you!' Kully yelled in exasperation.

'And robots... horrible horrible things.' things.'

The Doctor looked anxious. 'This s.p.a.cecraft, it wasn't sort of square like a tall wooden box...?'

Kully wrinkled his snub n impatiently. 'No, no, no...

that's not the s.p.a.cecraft. It's circular and flattish and silvery.'

Balan snorted scornfully.

'The blue box is somewhere else. By the black star,'

Kully chattered excitedly. 'The aliens were there. They were talking about destroying it,' he shuddered.

'The TARDIS!' Zoe and Jamie chorused.

The Doctor turned urgently to his young friends. 'We'd better go at once,' he cried.

Balan raised a restraining hand. 'My dear sir, you will be wasting your time,' he warned.

'My dear sir, time cannot be...' the Doctor stopped himself, turned and ran to the airlock. 'Come on, you two,'

he shouted.

Jamie hurried over, but Zoe held back. 'I think I'd rather stay here, Doctor,' she murmured.

The Doctor nodded. 'We won't be long,' he waved, opening the hatch. Before Zoe could object, they were gone. Filled with foreboding, Zoe wandered aimlessly round the module trying to ignore the fierce argument which had flared up between Kelly and Balan, while Teel and Kando occupied themselves with an elaborate communications unit along the far wall.

'I am sorry, Kully, but I can take no action until I have contacted the Director,' Balan concluded adamantly.

Kully grimaced. 'We all know what the old man will say. 'Do nothing.'

Balan struggled to remain calm. 'Better to do nothing than to cause unnecessary panic in the community.'

'Vegetables. Just vegetables the lot of you!' Kully snapped.

'Show' some respect!' Balan thundered. 'If not for me then at least for your father.' He swept over to the communications unit.

Teel indicated the useless strobing and flashing on the screen. 'There is powerful interference, Balan,' he reported apologetically. 'It is most unusual.'

'That'll be the robots..' Kelly muttered exhaustedly.

Zoe went over to the disconsolate little figure. 'You don't seem to be having much success convincing them,'