Gulliver took a deep breath, and finished: 'After some consideration I was of the opinion that this was altogether impossible.'

Jamie exploded with disappointment and frustration.

'Thanks for nothing! You're a great help!... I just wish the Doctor was here he knows all the answers!'

Far below at the foot of the cliff, where scattered rocks lay around the newly uncovered exit from the underground labyrinth, the Doctor and Zoe rubbed their eyes, blinking in the unexpected glare of daylight.

They had been travelling through the bowels of the earth, like moles, for so long they could not at first accustom themselves to so much light: and now they had finally made their way out through the new opening (unwittingly created by Jamie, had they but known it) they both had some trouble in focussing upon the prospect before them.

'It's a mountainside!' exclaimed Zoe, looking up in dismay, and tilting her head further and further back.

'Look at it it goes straight up for miles and miles... '

'I've told you a thousand times you must not exaggerate,' the Doctor reproved her mildly. But he followed her gaze, and screwed up his eyes again. 'Good gracious me look up there, right at the top of the cliff... Is this just another illusion, or do you see what I see?'

Zoe's vision was blurred; a kaleidoscope of towers and turrets, domes and battlements swam crazily together and settled slowly into place.

'It it looks like an old medieval castle,' she said doubtfully.

'Of course! The citadel!' The Doctor clapped his hands.

'Now we're getting warmer at last... Don't you remember, our friend Gulliver referred to the Master as living in "no regular edifice, but a citadel like a walled town, at the top of a hill or cliff which is reckoned the highest in the kingdom"... This must be the place!'

'You think the Master's up there?' Zoe asked.

'I'm quite certain of it. It won't be long before we meet him face to face I must say I can hardly wait.'

'Well, I I must say you're going to have to be patient! must say you're going to have to be patient!

How do you suppose we're ever going to get to the top? It's a very long way to climb.'

As they peered up at it, silhouetted against the brilliant sky, the Doctor became aware of a strange, high-pitched whistling sound. It seemed to be coming closer and closer like a giant mosquito or a sh.e.l.l fired from a cannon or -.

'Look out!' he shouted suddenly. ' Duck Duck, Zoe!'

They threw themselves flat upon the stony ground, and the missile whatever it might have been pa.s.sed harmlessly over them, before exploding in a lurid flash of searing white light against the cliff face.

A cloud of dust enveloped them for an instant, then slowly began to fade, leaving them choking and spluttering.

'Whatever was that?' Zoe gasped.

'I haven't the faintest idea... Except that it seemed to be aimed at us and rather too accurately for my liking!'

Zoe lifted her head, wiping the dust and grime from her face with the back of her hand, and said in an apprehensive whisper: 'Doctor... When that thing exploded against the rock am I imagining it, or did you see a word in the middle of the explosion? As it flared up like a bolt of lightning in the middle of it, in a sort of star-shape, I thought I saw the word BOOM BOOM... Did you see it too?'

'Thank heavens I thought I must be going a little crazy,'

the Doctor agreed gratefully. 'Yes BOOM BOOM in capital letters, and with an exclamation mark after it... What can it mean?' in capital letters, and with an exclamation mark after it... What can it mean?'

As if in answer to his question, they both heard a sudden, ear-splitting shout like a war-cry: a wordless yell of hatred. But the strange part was at the same moment, they both saw a balloon float up above the rocks: and the balloon contained the single word: YARGHRROO! YARGHRROO!

'It's no language I ever came across before and yet it seems vaguely familiar.' The Doctor pondered this little puzzle. 'But where are these words and non-words coming from?'

A sudden rattle of loose stones alerted them, and they swung around to find they were no longer alone.

The figure that confronted them was an awesome sight.

For one thing, he was a giant of a man: a towering Hercules, with bulging muscles, which looked all the more remarkable since they were outlined upon his torso in a spider's web of deep purple lines... And his skin was bright green.

By way of clothing, he wore a pair of shining purple tights and thigh-length silver boots: around his naked, ma.s.sive shoulders there swirled a black silk cape, and on his bullet head he wore a black skull cap and a half-mask.

And in his hands he carried a very extraordinary ray gun, made of' glittering plastic and metal.

Zoe gave a cry whether of fear or of recognition, it was hard to tell and exclaimed: 'The Karkus!'

Strangest of all, the man stood posed and motionless for a few seconds, as if frozen to the spot, then he announced in a thick, guttural accent: 'You... are... my... prisoners.'

'That remains to be seen,' said the Doctor, trying to appear casual. 'But first perhaps you should introduce yourself, my good man. Who are you?'

'I... am... the... Karkus,' came the reply, in the same thick, metallic voice.

'I told you, he's the Karkus,' Zoe hissed urgently, in the Doctor's ear. 'Spelled K-A-R-K-U-S and p.r.o.nounced "carcase", on account of his physique... Don't ever let him get you in a hammerlock.'

'I wouldn't dream of it dear me, now what is the fellow playing at?'

For on the word 'hammerlock', the newcomer had suddenly changed his position, adopting an even more menacing stance, and pointing the ray gun at the Doctor's head.

'Raise... your... hands... above... your... head,' the grating tones went on. 'Obey... or... I... fire!'

'That pea-shooter?' The Doctor laughed gently. 'Forgive me but what kind of weapon is that supposed to be?'

Zoe said urgently: 'That's his anti-molecular ray disintegrator he never goes anywhere without it.'

'Stuff and nonsense,' said the Doctor. 'Anti-molecular, my left foot such a weapon is scientifically impossible it doesn't exist.'

And as if to prove his point, as he said these words, there was a sharp ping ping, and the ray gun abruptly disappeared.

(As it vanished, they noticed that the word PING! PING!

materialised for a moment between the Karkus's empty hands.) The Karkus discovered that he was unarmed and froze again, clenching his fists in a very threatening manner, and uttering a fearful guttural noise at the back of his throat.

(Above his head floated the word GHRRRGH! GHRRRGH! ) ) 'An interesting spelling,' said the Doctor, 'but not, I fancy, to be found in the Oxford Dictionary.'

'I... tear... you... limb... from... limb!' articulated the Karkus, with some difficulty.

'Oh, Doctor, please be careful he could do it, you see the Karkus has superhuman strength... Try not to annoy him.'

'Annoy him? My dear girl, I never saw him before in my life, why should I want to annoy him him? He's beginning to annoy me me with his sub-human manners and his lack of civilised conversation... ' with his sub-human manners and his lack of civilised conversation... '

Before he could finish, the Doctor found himself being grasped by two colossal hands, each one as big as a leg of mutton, only bright green. The Karkus lifted him several feet off the ground, and Zoe screamed: 'Take care, Doctor remember he's only a fictional character too say you don't believe in him '

The Doctor exclaimed irritably and a little breathlessly, from his uncomfortable position in mid-air: 'Believe in him? I don't believe or disbelieve how can I? I never even heard of him till now my dear fellow, kindly put me down!'

The Karkus gave another terrifying cry ( YEEIKE! YEEIKE! ) and dumped the Doctor unceremoniously on the ground. ) and dumped the Doctor unceremoniously on the ground.

( SPLAT! SPLAT! ) Then he seemed as if he were about to jump upon him like an all-in-wrestler but he was distracted at the last moment by Zoe, who walked up to him with a polite smile, and one hand outstretched, saying: 'How do you do? My name's Zoe so nice to meet you.' ) Then he seemed as if he were about to jump upon him like an all-in-wrestler but he was distracted at the last moment by Zoe, who walked up to him with a polite smile, and one hand outstretched, saying: 'How do you do? My name's Zoe so nice to meet you.'

The Karkus turned as jerkily as before to face her, with a puzzled green frown beetling his brows. The Doctor struggled to his feet, calling out: 'Zoe have you gone mad? What are you doing?'

'Lesson Seventeen, from Basic Course in Self-Preservation I learned this at Mind-Training School,'

said Zoe airily.

Then everything seemed to happen at once: the Karkus grabbed her hand, and Zoe threw her weight sideways and downwards and amazingly the mighty creature suddenly flew through the air, grunting with pain as he hit the rocky floor. ( UH! UH! ) ) He quickly recovered, picked himself up, and made another, murderous attack upon Zoe, who muttered, 'Lesson Eighteen B,' and sidestepped.

She gave another expert flick of her wrist, and he fell the other way this time. ( OUCH! OUCH! ) ) The Doctor tried to go to Zoe's a.s.sistance but she seemed to be managing very well without him. As the Karkus made one last a.s.sault Zoe countered with a throw that sent him flying, head over heels, landing flat on his back.

At once, she put her foot under his chin hard and remarked: 'You'd better give up, you know. The carotid artery can only take a certain amount of pressure.'

'Mercy... Mercy!' grunted the Karkus.

'Do you submit?' asked Zoe.

He slapped his hand flat on the ground: and she lifted her foot.

'That's more like it,' she said cheerfully. 'And don't be so silly another time, there's a good boy.'

The Karkus dragged himself painfully to his feet, saying: 'I... am... your... slave... Command... me.'

Zoe turned to the Doctor: 'We may as well get him to help us he's not a bad lad, at heart in fact, as long as he's on the right side, he can be a tower of strength.' To the Karkus, she said, 'Do you know the best way to get to the Citadel?'

'I... know... it...

'Then take us there as soon as possible.'

The Karkus had lost his black silk cape in the struggle, and now he set off among the rocks without it. The Doctor automatically picked it up and put it on: it seemed the easiest way to carry it. As the muscleman disappeared into the distance, he asked quietly: 'Who did you say this chap is exactly? You mentioned a fictional character, but I'm afraid I can't quite place him... '

'Oh, you must must know the Karkus!' exclaimed Zoe. 'We all follow his adventures at home in the strip section of the know the Karkus!' exclaimed Zoe. 'We all follow his adventures at home in the strip section of the Hourly Telepress Hourly Telepress.'

'Strip section? Ah, that explains it!' Light dawned, and the Doctor's face broke into a smile. 'He's a character from the comic strips of the year 2000... That accounts for all those amazing words and balloons and the way he kept freezing into one position after another I see it all now...

Only I'm afraid I never heard of him.'

'But surely you've been in the year 2000 '

'Ah, yes, indeed a nice place to visit, but I wouldn't want to live there... and quite frankly, I was rather pre-occupied with other matters at the time... I had very little opportunity to follow the comic strips.'

'Well, we'd better start following this this one!' Zoe advised him. 'He must be halfway up the cliff by now!' one!' Zoe advised him. 'He must be halfway up the cliff by now!'

The comic strip giant may not have had a great deal of intelligence in his granite skull, but he certainly knew the best way to climb up to the Citadel. And though he had a physique like a lumbering ox, it was quite surprising to find that he could move as lightly as any gazelle when the need arose.

Now he led the way up a narrow track, littered with fallen stones, picking his way confidently between one boulder and the next. Zoe and the Doctor did their best to catch up with him but he had a head start, and it wasn't easy.

The track zig-zagged back and forth along the lower slopes of the cliff face, and then took an unexpected turn and burrowed under a natural arch in the rock, disappearing for a few yards, and then appearing again around the side of the escarpment.

Here, the going was rougher, and the path became steeper: then it turned another corner, and suddenly, dramatically, transformed itself into a flight of stone steps, that led upward on and on as if they would reach out and touch the sky.

The Doctor and Zoe had long since stopped talking: they needed all their breath for a climb like this! Now they exchanged unhappy glances, and soldiered on, up those never-ending steps...

It seemed as if they would never reach their goal, but at long last, breathless and groaning, they found themselves on a narrow terrace, fringed by a stone bal.u.s.trade, and there, facing them, was an imposing pair of oaken doors, flanked by two st.u.r.dy pillars.

The Karkus, who was not at all out of breath, bowed obsequiously to Zoe, and indicated the old fashioned iron bell-pull beside the double doors.

'Oh ah thank you... Very much,' panted Zoe.

'Yes thanks my dear er ' The Doctor whispered in Zoe's ear: 'What did you say his name was?'

'Karkus. K-A-R-K-U-S... '

'Yes, quite absurd, of course but nevertheless... Thank you, Mr Karkus, I don't think we need trouble you any further.'

Zoe added: 'That's right we shan't be requiring you any more. You can run along now.'

'I... obey... ' said the Karkus: and with one last, low bow he took his leave of them, shambling off along the terrace, and out of sight around the corner.

The Doctor mopped his brow absent-mindedly with the corner of the black silk cape and realised belatedly what he was wearing.

'Oh how very tiresome the poor fellow's gone off without his cloak oh, well, it's too late to call him back now. And you never can tell it might come in handy!...

Let's go.'

He advanced towards the bell-push, but Zoe tugged at his arm. 'What are you doing? We can't just ring the bell and walk in!'