[Part one]

My life is an endless journey across the bounds of space and time. A Time Traveller, drifting amongst the great galaxies of the universe.

(The TARDIS materialises.)

The TARDIS made an uncomfortable landing It was as though we had been plucked from the sky by some vast magnetic force, pulling us down into its web.

(The sound of waves and seagulls.)

Of course, I had no idea where, or in which period of time we had arrived, but we had materialised onto an isolated stretch of beach miles from any visible signs of habitation. It was a cold, unwelcoming winter's night with curling white foam gently lapping the shore. And all around us, deep mud banks stretching for as far as the eye could see.

(A seagull flies overhead.)

My companion Sarah Jane and I decided to explore our bleak surroundings. But as we stepped out into the freezing darkness of the night, we were both overwhelmed by a feeling of deep apprehension. A feeling that we were not alone.

SARAH: Doctor. Doctor, where are we?
DOCTOR: I don't know, Sarah. But whereever it is, I have an uncomfortable feeling we're not very welcome.
SARAH: What do you mean?
DOCTOR: It's all too quiet. Only the sea and the wind. This beach must stretch for miles, and yet I've got the feeling that we're not the only ones here. As though we're being watched.
SARAH: Doctor, if you're trying to give me the creeps, may I say you're doing a very good job?
DOCTOR: What month is it, Sarah?
SARAH: February, I think.
DOCTOR: We could be somewhere in England.
SARAH: How can you tell?
DOCTOR: Well, position of the stars, wind direction, temperature.
SARAH: Yes, I'm glad you mentioned temperature. It's like the arctic out here. Even my goose-pimples have goose-pimples. Hey, wait a minute. Hey, Doctor, come over here. Have a look at this.
DOCTOR: What is it?
SARAH: A notice board.
DOCTOR: What does it say?
SARAH: I won't know till you shine your torch. Ah. Ministry of Defence. It is dangerous to swim from this beach at any time. Keep out.
DOCTOR: Swim? The tide's so shallow here I doubt there's enough water to paddle in.
SARAH: Well then, why is it so dangerous, hmm? Oh well, I suppose we must be grateful we're back in good old civilisation again.
DOCTOR: There are some lights over there in the distance. Looks as though they're miles away on the other side of the bay. We'll never make it on foot.
SARAH: Especially with all this mud around. Ah!
DOCTOR: Sarah, what is it? What are you looking at?
SARAH: Oh, on the beach here. Look.
DOCTOR: Some kind of seaweed.
SARAH: I've never seen seaweed like that before. It's more like a baby octopus. Yes, look at that eye. Yuk, horrible.
DOCTOR: Yes. And the tentacles, like tinfoil. It's made out of some kind of metal substance.
SARAH: You know, you're right. It is quiet. Not even a wind now. Oh, Doctor, why don't we just go back to the TARDIS?
DOCTOR: Listen!
SARAH: What?
DOCTOR: Shush, shush. Can't you hear it? That sound.
SARAH: I can't hear anything. Oh, Doctor, you're doing it again. You're trying to scare me. Stop it.
DOCTOR: Shush, shush. No, Sarah, listen. Don't make a sound. Don't even breathe. Just listen.

(The soft sound of thump, thump. Thump, thump.)

Something was moving in the sand dunes nearby, slithering its way towards us along the beach. What kind of beast it was, we couldn't tell, but all the time it was getting closer, closer, breathing, searching, hunting. Then suddenly, as the moon began to emerge from behind dark clouds to give us our first glimpse of the beast that was stalking us

SARAH: Doctor!

(Roar!)

We didn't wait to find out what it was that had leaped out at us from the shadow, for we just ran and ran faster than I would have thought possible. All I can remember is that I was so terrified that I tripped over my scarf perhaps twelve times, or maybe thirteen.

(Roar with lots of vibrato!)

However, we soon discovered that our travels had brought us back into the present day. We were on the east coast of the British Isles, where the waters of the great River Thames flow out into the sea. An underwater expedition organised by the government had apparently just vanished without trace from the bed of the estuary. They had been searching for some kind of meteorite which had dropped into the sea some years earlier, causing serious flood damage all along the River Thames, even into the City of London itself. Now, as you know, I have spent a great deal of my travels avoiding the dazzling array of meteorites which tumble across the darkness of space like millions of bright stars, so it did seem curious to me that with all the complicated technology man has created for himself in this twentieth century, he was unable to locate what is, after all, nothing more than an old piece of stone. But Professor Emerson, the eminent astronomer, assured me that what they were looking for was no ordinary stone. For not only was this the third expedition to be lost without trace, the river itself was beginning to show signs of radioactive contamination.
Defying the Professor's stern warnings of the dangers involved, I decided to undertake my own investigation of the seabed. Down, down into the murky waters of the estuary I plummeted. It was an awesome experience. Down, down. My feet finally came to rest on the muddy seabed sixty feet below the surface of the estuary. It was dark, and the water was clouded with the sand which my own arrival had disturbed. But to my intense curiosity, I was totally alone. No signs of that marine life which forms such an essential part of a underwater world. No shoals of tiny shimmering fish to dart in and out across my path. I was alone in a deserted wildenness.
My explorations lead me to the mouth of a gigantic cavern, which I estimated had been formed by the impact of the falling meteorite. Inside the cavern, I followed the path of an irregular shaped tunnel which had been hollowed out beneath the seabed, and with no visible end. The water was becoming colder and darker, a clear sign that the tunnel was plunging down still further into the depths of the seabed. It was getting narrower and narrower, like the gallery of a vast subterranean catacomb. Eventually I found myself taking a turn to the right. As I did so, something brushed against me. I couldn't see what it was. I could feel something entwining itself round my ankle, holding me in a vice-like grip. I couldn't move. And now my body. All the life was being squeezed out of me. My arm. Something was wrapping itself around my arm. I dropped the sea-lamp. It floated away from me, but as the light filtered back through the darkness, I caught my first glimpse of the alien force that was slowly curling itself around my entire body. A living weed, clinging to me like the tentacles of a giant deep sea octopus, crushing my bones and preparing to feed off me. It was the same metallic weed that Sarah Jane and I had found on the beach, and which was now glistening in the underwater light, its huge emerald eye penetrating the dark, its tentacles strangling, tugging, dragging me down. I struggled to free myself, but the dazzling tentacles were cutting into my flesh like sharp wire. The phenomena was all around me. The very blood in my body was being drained away.
But suddenly, it stopped. Something had happened, for the tentacles of the alien weed released their stranglehold on my body and disappeared into the darkness of the tunnel, almost as though it had never existed. But why? Where had the phenomena come from? Where did it go to? Was it the spawn of some far greater alien lifeforce, just lying in wait for the intrusion of every unsuspecting underwater traveller? And what was it there to protect? For a few moments, I just drifted alone in the cold waters of the tunnel, trying desperately to regain all the energy that had been sapped out of me by the life and death struggle with the alien weed. Eventually I managed to recover my sea-lamp, but the scene it illuminated was one that I never again hope to witness. All around me, floating up and down rhythmically with the movement of the water, was all that remained of the underwater expeditions that had preceded me. A scattering of disconnected human bones and skeletons, with gaping sockets where eyes had once been. Eyes that had been staring out hopelessly, begging for the help that had never come.
Moving deeper and deeper into the heart of the tunnel, I gradually became aware of a bright fluorescent glare reflected on the tunnel walls just ahead of me. I drifted closer, and I discovered that I had reached the final resting place, not of the meteorite, but of some vast cylindrically shaped spacecraft, the remains of its metallic frame glistening in a pool of blinding light. I tried to shield my eyes, for although the machine had burnt itself out long ago, its metal structure still retained a high intensity glow. I moved in cautiously for a closer look. The surface of the machine was scored with deep claw marks, as though the occupant had been involved in some life of death struggle to get out. Suddenly, the air in my diving helmet seemed to be getting thinner. There was a pressure in my throat as though I was being strangled. A heartbeat. That same chilling sound I'd heard on the beach. Now it was in the tunnel. As I turned my sea-lamp into the darkness, I could see the creature propelling itself towards me. I had to get away. Away. Away! My worst fears had been realised. That tunnel, the burnt out spacecraft. I had seen it all before, a long time ago.
Sarah Jane helped me out of the water, and I warned her of the threat we were now facing. I knew the enemy we were up against.

SARAH: Pescatons?
DOCTOR: Cunning, ravenous creatures, half human, half fish. Their origins are in the carcharhiniae.
SARAH: Er, say that again?
DOCTOR: Carcharhinidae. Deep sea water species, like the shark.
SARAH: Shark?
DOCTOR: Yes. And just as mean. The Pescatons are the most voracious, hostile creatures I've ever known. They'll attack and feed off anything that they come into contact with
SARAH: Well, what do they look like, these Pescatons?
DOCTOR: Hmm? I suppose you could say they have a head and body with the shape and texture of any of the shark species.
SARAH: Teeth?
DOCTOR: Sharp as nails. Fins like claws. Out of water they'd tower over any of their human victims.
SARAH: But how do they move?
DOCTOR: Slowly, on two webbed feet. More like some prehistoric beast.
SARAH: Fish who can build a spacecraft and fly off to other planets?
DOCTOR: Yes.
SARAH: Sounds a bit far-fetched to me, Doctor.
DOCTOR: Sarah, the Pescaton civilisation has developed a technology which is far superior to anything here on Earth. These creatures possess amazing powers.
SARAH: What are they doing here? Where did they come from?
DOCTOR: They come from Pesca, a planet that was once covered with vast oceans. Not any more. Now it's nothing but a wilderness.
SARAH: You mean you've actually been to this planet?
DOCTOR: Well of course I've been there. I think it was some time back in the fifteenth century.
SARAH: The fifteenth century? Well, just how old are you?
DOCTOR: Pesca belongs to a dying solar system. As the sun draws it closer and closer toward its centre, every ocean on the planet will evaporate. Do you understand, Sarah? The Pescatons are desperate to escape before their planet completely disintegrates.
SARAH: But, well, that creature we heard on the beach and on the seabed, are you telling me it found its way here to Earth across millions of miles of space?
DOCTOR: Yes. An advance guard, Sarah. The first of the Pescaton migration

Buffoon, an eccentric, a liar. That's what the experts called me as they listened to my extraordinary account of the underwater discoveries I'd made inside the cavern on the seabed. Professor Emerson dismissed as pure fantasy the idea of a sea creature migrating from a planet that he and his astronomer colleagues had never even located. Fantasy or not,

(Screams. Roars. Screams.)

out of the river it came, right into the very heart of London itself. The people of this capital city were stunned, helpless against the might and power of such a gigantic force. Their worst nightmares had become a reality. A creature from another world was amongst them.

(Screams, car horns, roars, emergency sirens.)

As day turned into night, and long dark shadows stretched across cold frosty pavements, the city became paralysed by an ominous silence. There was an air of expectancy, as the bewildered people of London waited for the next onslaught by their frantically hostile invader from another world. But the Pescaton, now noticably weaker in its desperate search for salt water, had retreated into a canal, to emerge later in somewhat different surroundings.
The creature shuffled its way across the deserted grounds of the London Zoo, its strength gradually declining. For like any fish out of water, it couldn't hope to survive Earth's atmosphere for more than a few hours at a time. But the Pescaton threat was far from over, and if it was to be destroyed, the creature had to be denied access to anything that would help to reactivate its main organic system. But time was running out for the Pescaton. The creature slumped to the ground and lay there like some prehistoric monster, its heart pulsating, until gradually fading to silence. Not a movement. We waited tensely, hardly daring to say even a word. Was it all over at last? Was this unparalleled challenge to our power of logic finally silenced? Several minutes passed. I saw two human figures emerge from the shadows. Defying my warnings, they slowly approached the body of the creature lying there crumpled up and lifeless beneath the glare of the great bank of floodlights. There was an air of jubilation in their voices as they called back the news that the creature was dead. More daring figures emerged from the shadows, all eager to satisfy their curiosity. Soon the Pescaton creature was engulfed by a crowd of onlookers. Zoo officials, police constables, soldiers, newspaper reporters. Everyone agreed that this was a night they would never forget. Little did they know how right they were.

(Roar! Screams.)

Without warning, the creature reared up again, striking out at its tormenters with unrelenting fury. The crowd scattered in panic. Even in the lion house, the undisputed kings of the jungle shrank to the back of their cages in terror. But for some it was too late. The creature's teeth moved swiftly, plucking out the terror-stricken crowd one by one, tearing at their flesh, hurling them with uncanny strength against the endless rows of animal cages. But although the Pescaton threat was not yet over, its new-found strength was gradually subsiding. As if drawn by a magnet, the creature's natural instinct led it towards its one last means of survival. The Aquarium house. Here at last the Pescaton would find the protection it was looking for. Salt water, and the chance to feed off those other creatures from the deep which would be powerless against such a ravenous attack. The Pescaton had to be stopped!
I picked my way cautiously into the long dark Aquarium hall, flanked on either side by huge illuminated glass tanks bulging with fish. Fins, slimy scales, shells, claws, tentacles. It was an uneasy feeling to know I was being watched by hundreds of penetrating eyes, waiting, watching. For a moment, I just stood there and listened. Silence. The creature was lurking in the dark somewhere. I couldn't see it, but I knew it was there. And yet, not a sound. Not even a movement. Could it be that the Pescaton's strength had finally expired? A heartbeat. Still alive. Rearing up out of the shadows at the other end of the hall, I could see the slits of the creatures eyes glaring through the dark like bright emeralds. Suddenly and with superhuman strength

(Roar! Glass breaking. Water sloshing.)

The Pescaton lashed out at one of the glass tanks. Water came rushing out in a great torrent, sending fish of all shapes and sizes wriggling onto the floor. I tried to get away before all the other huge tanks came tumbling down on top of me. And then the Pescaton collapsed to the floor. It was all over. For a moment, I just stood there, too frozen with fear to even move. And as I looked down, before my very eyes, the creature's flesh was disintegrating. Within seconds, all that was left was the vertebrae of a large fish. It was all over.
At last, the bewildered people of London were able to return to their daily lives without constant fear of the unknown. The relief was enormous. But that night the sky above the city was dazzled by the blinding lights of meteorites, as they dropped one by one into the murky waters of the River Thames. The Pescaton invasion had begun.

[Part two]

The Pescaton invasion had begun. From every corner of the globe, reports were coming in of meteorite landings in the sea. It could only be a matter of time before the signal was given for the start of the great mass migration itself. The migration to Earth of the whole Pescaton civilisation. We were on the brink of colonisation by the most bizarre and hostile invader mankind has known. But when would the signal come? And who would give it? To know the answer, it was necessary for me to cast my mind back to that extraordinary time when the TARDIS was drawn into into the magnetic field of the dying planet of Pesca.

For thousands of years Pesca, a planet in the constellation of Pisces, the last sign of the zodiac, had been dominated by vast oceans. But as the planet's orbit was bringing it closer and closer to the sun, the deep blue waters of the Pescan seas were drying up, destroying all forms of marine life that had existed there for perhaps millions of years.

I stepped out of the TARDIS onto hard baked soil, surrounded on all sides by a parched, almost desert, landscape. In the distance I could see the peaks of high, craggy mountains which had clearly once been topped with snow, but were now streaked yellow with the lack of moisture. There were no trees, no signs of any vegetation or animal life, and the soil itself was lined with gigantic fissures indicating recent seismic activity. It was a sad and desolate panorama laid out before me. No colour, no life, only the remnants of a past. But what kind of past? For the only clue I was to get was on a stretch of golden sand that had once been a sea shore. There, the rocks were indented with the marks of beautiful sea anemones, shells, and many other forms of exquisite marine life. I could move only slowly, for there was no shade from the hot cruel glare of the sun, and I felt stifled and isolated, as though I was the only living thing on the entire planet. But as I reached the banks of what had once been a fast flowing river, and started to make my way across to the other side

DOCTOR: Argh!

The soil on the river bank had given way beneath me. I was falling down into a deep, dark, endless chasm. Down, down, down.

(The sound of moving water.)

How long I lay there in the dark I'll never know, for my eyes were firmly closed and I couldn't move, as though the whole of my body was paralysed. I seemed to be stretched out on the floor of some vast cave, for I could hear the hollow sound of water gently lapping against the rocks. This, I later discovered, came from one of the many salt water lakes which had been dug out from beneath the surface of the planet like great reservoirs. But at least it was a pleasant, restful sound, until. My eyes popped open. There were Pescaton creatures everywhere, their bodies pulsating to the rhythm of their own heartbeats, and long pointed teeth glistening green in the light from their own eyes. But towering above me was a creature more gigantic that all the rest, with a head that was oval-shaped and too big for its body, all of which was covered with shiny metallic scales. But it was the eyes. I became transfixed by its eyes. They were transparent, clear like glass, like emeralds. I could see right into the very brain of the creature itself as it opened its mouth to speak.

ZOR: We have been waiting for you, Doctor. We knew you would come.
DOCTOR: Who are you? I mean, what are you? What do you want of me? I, I can't move.
ZOR: I am Zor, leader of all Pescatons. You are our prisoner, Doctor. You have been brought here to help us.
DOCTOR: No one can help you. Your planet is dying. The sun is burning you right out of the cosmos.
ZOR: You will show us the way to our new world. We shall use your special powers to find a planet where the sun can no longer harm us. The Pescaton civilisation must not die.
DOCTOR: Oh? Really? And may I ask how you propose to stop it? From what I've seen of this planet of yours, there's hardly enough salt water left to fill a tea cup.
ZOR: You will help us, Doctor.
DOCTOR: Listen, Zor. Are you listening? I'll never help.
ZOR: The eyes, Doctor. Look into my eyes.
DOCTOR: No. No, I won't .
ZOR: I, Zor, command it. The eyes, Doctor. The eyes.
DOCTOR: No!
ZOR: Look, and you shall see.
DOCTOR: No. No!

Staring into the creature's eyes, I had felt all life was ebbing from me. What I had seen were the inner workings of an incredible machine, the brain of Zor himself, like a vast computer, the nerve centre of the entire Pescaton species. The hypnotic beam had torn into my mind like a sharp dagger. We had been locked in mental battle as the mighty Zor had struggled to absorb my knowledge of the galactic universe and solar system. However, my resistance was more than the Pescaton leader had anticipated, and his mental pressure was no match for the special powers that I had been gifted with. I found my way back to the surface and escaped from the evil that had almost engulfed me on the planet of Pesca. For as the TARDIS finally released itself from the powerful magnetic force that covered the planet, I was left with a deep apprehension that this was not the last time I should be matched against the hostile civilisation I had left behind.

(Big Ben strikes six o'clock.)

After the first wave of meteorite landings, an uneasy calm had settled over the rooftops of London. For centuries, the great capital city had been a thriving, bustling metropolis, the very heart of the nation. But that heart was now as quiet as the grave. Streets were deserted, doors and windows bolted, and the sounds of life curtailed. At dusk, voices were only raised to a whisper. The invader's name had become become a household word, a name to fear.

Rush hour near Saint Paul's Cathedral, that glorious dome of a bygone age. A police constable patrolled his beat on empty pavements. No office workers rushing to catch buses or tube trains. No traffic jams to congest the streets. At Billingsgate Fish Market, the nightly gathering of London's cat population went hungry. In Trafalgar Square, there was no one to feed the pigeons. And in Piccadilly Circus, snowflakes began to fall and settle. But it was towards the river that all eyes were turned. The city and its ancient river, now quiet and waiting. Waiting in fear of what was yet to come. As a bright February moon flicked in and out of dark clouds, the skipper of a river tug steered his vessel towards the great Pool of London.

(Tug horn, Pescaton roar, crew shouting.)

The attack came with swift and sudden fury. The Pescaton reared up out of the water and hacked its way into the tiny vessel with overpowering strength. The crew fought for their lives as the voracious shark creatures circled their wreckage, swooping in finally for the kill.

One by one, the advance guard of the Pescaton invasion were emerging from the river, all the way from the sea into the very heart of London itself. The attack was on. The alien army of invaders was rampaging across the city, striking down everything in its path. In a massive assault by one of the raiders in a crowded London street, a double-decker bus was smashed over onto its side. With unleashed fury, the creature tore into the metal framework of the bus as though it were a child's toy, sharp teeth and claws plucked the terrified passengers out.

Everywhere the danger was escalating. Schoolchildren were terrorised in their classrooms. A building worker was plucked from the cabin of his crane and hurled into the river. A terrified flower seller played cat and mouse with one of the creatures in the forecourt of a railway station, and lost. Electricity supplies were disrupted as generators were demolished. Police cars, fire engines, railway trains, even army tanks were no match for the all-powerful invader. All who remained in the creature's path did so at their own peril.

(A baby cries.)

SARAH: Doctor, over here, quick.
DOCTOR: Hello. Hello, little baby. Where do you come from , then? He won't talk.
SARAH: He can't talk. Look, I found it outside the shop over there. Let's trying and get back to its mother.
DOCTOR: The place is crawling with Pescatons.

(Machinegun fire.)

SARAH: Oh, what's the matter with the army? All their sophisticated weapons, and they still can't find anything to bring down these Pescatons.
DOCTOR: It's not as easy as that, Sarah. No weapons are effective enough to hold off this kind of attack. No bullets, no bombs
SARAH: But why not?
DOCTOR: Pescatons have a skin like steel.
SARAH: Steel?
DOCTOR: Don't ask me to explain the organic structure of these creatures.
SARAH: Why not?
DOCTOR: Because I haven't a clue.
SARAH: Oh.
DOCTOR: All I do know is they've developed some kind of protective body shield which is far superior to anything we know about.
SARAH: Which only goes to show how little we know about anything on this ridiculous planet of ours.
DOCTOR: Your planet, Sarah, not mine.
SARAH: Oh, don't quibble, Doctor. The Pescatons are destroying the whole of London and there's not one single person who can do anything about it. Is this what they call advanced civilisation?
DOCTOR: It's not what I call it, so don't blame me.
SARAH: I'm not blaming you. Oh, be quiet, baby. Shush. We've got enough problems on our hands.
DOCTOR: I've never known you to be so tetchy in the face of danger.
SARAH: Oh, who said I'm tetchy! I'm just angry, that's all. None of this need have happened.
DOCTOR: You're tetchy. And do you have any suggestions as to how it could have been avoided?
SARAH: Yes. Everyone should have been prepared. I mean, you and I have been together long enough to know there are plenty of hostile planets throughout the universe, and any one of them could do what the Pescatons are doing now.
DOCTOR: Yes. No one ever believes something like this can happen to them until it's actually on their own doorstep.

(Roar!)

SARAH: Doctor! The other end of the street!
DOCTOR: Keep back, keep back. Just leave this to me.
SARAH: No, Doctor! You'll be torn to pieces.
DOCTOR: I'll try and get it away.

(The baby screams.)

DOCTOR: Take the baby and make for the main road. I'll join you there as soon as I can.
SARAH: No, Doctor, I'm not leaving you. Doctor. Doctor!

The creature reared up, its long pointed teeth moving in for the attack. For one moment it looked as though the creature was going to ignore me and claw straight into Sarah Jane and the baby. To regain its attention, I had to do just about everything except turn a cartwheel. Thinking about it, I'm not too sure I didn't even do that. Anything I could lay my hands on I threw at it. Stones, dustbin lids, milk bottles, even an old boot somebody had discarded in rather a hurry. But still the creature ignored me and slithered closer and closer towards Sarah Jane and the baby.

SARAH: Doctor!

(The baby cries.)

Finally I discovered the one secret weapon that no respectable creature worth its salt could resist. I sang and danced.

DOCTOR: (singing) Hello, Dolly. Well, hello, Dolly. It's so nice to have you back where you belong.

It worked. The creature turned its attention from Sarah Jane and the baby and came towards me. Singing and dancing dementedly into a side street, I managed to give it the slip. Sarah Jane and I met up again later. It was a narrow escape for us, but elsewhere the battle went on. The Pescatons seemed invincible. Something was puzzling me. Without the direct control of their nerve centre, the power of these alien sea creatures was useless. So how, then, were the invaders being activated? Unless, what if their leader, Zor himself, were already here on Earth, directing the invasion like a commander in the field? If Zor was here, then he had to be found without delay. Only then could the invasion be stopped.

The first wave of attacks came to an end, for if they were to survive, the Pescatons needed the protection of salt water. One by one, the invaders retreated back towards the Thames. But some were not so lucky. In a desperate attempt to reach the river, one of the creatures had become trapped inside an Underground tunnel, clearly immune from the high voltage electricity. Sarah Jane and I decided to go after it, but it was an experience I shall not forget. In future, I shall travel only by bus. The last train of the day had gone, the electricity supply turned off. Moving cautiously, close to the walls, Sarah Jane and I picked our way into the darkness of the Underground tunnel.

SARAH: Doctor? Doctor, I think we should turn back.
DOCTOR: Shush. I'm listening to the walls.
SARAH: Walls? What for?
DOCTOR: Vibrations. There's something in the tunnel ahead. I can feel movement.

(He starts playing a high-pitched musical instrument.)

SARAH: Doctor! Doctor, what are you doing? This is a fine time to start playing your piccolo.
DOCTOR: I always play the piccolo when I'm nervous. Relieves the tension.

(He resumes his playing.)

SARAH: Doctor, look out! Behind you!

(Roar!)

DOCTOR: Let's get out of here, quick.
SARAH: No, Doctor, wait a minute. The creature. Look at the creature. There's something wrong. It's trembling, shaking.
DOCTOR: Get out of the way, Sarah. Get out of the way!
SARAH: No, there's something wrong, I tell you. The music. Quick, Doctor, play your piccolo again.
DOCTOR: What? What do you take me for, the Pied Piper?
SARAH: Doctor, do as I say, quickly.

(He plays, the Pescaton roars.)

SARAH: Louder, Doctor. Louder! Look, its running away, Doctor. The creature's going, It's backing away down the tunnel.

I must say, I had no idea my musical talent would be so enthusiastically received, for it certainly had the desired effect. Quite unwittingly, we had stumbled upon the one effective enemy of the Pescatons. An enemy as repellent to those alien creatures as it is to so many of those killer sharks who mercilessly ravage the oceans of planet Earth. That enemy was noise. High-pitched noise.

The hunt was on. If we were to prevent the migration to Earth of the entire Pescaton species, then our only hope was to seek out the nerve centre of that species and destroy it. Zor, their creator, had to be destroyed. But time was running out. Soon the hot rays of the sun would be moving in for the final destruction of the planet of Pesca. Soon the planet would be no more than a vast galaxy spread across the dark, endless night of space. At last our chance came. During the lull that followed the first wave of attacks, reports were coming in which described a different, more terrifying creature which was taking refuge in a sewer somewhere beneath the city streets. The description of this gigantic beast, with an oval-shaped head and a body covered with shiny metallic scales, soon confirmed my suspicion that we had located the lifeline of the Pescaton civilisation, their leader, the all powerful Zor. With the help of Professor Emerson, I set up high frequency electronic sound equipment round the walls of a cavity which was built into the sewer duct. If I could only find a way to lure Zor into that cavity, the sound beam would activate a blow deadly enough to cut right into his brain.

Alone in the dark, again, waiting. Waiting for the final confrontation which would decide the destiny of two great civilisations. One good, one evil. But what would happen if the sound wave failed to work? Hadn't Xor proved himself to be invincible, to be all-powerful? And what would happen if I myself succumbed to those powers? I waited anxiously, but not for long.

ZOR: We meet again, Doctor.

His eyes were fixed on me, penetrating the dark. And his whole body, expanding to the pulsating rhythm of his own powerful heartbeat.

ZOR: We meet again, Doctor, for the last time.

He moved closer and closer towards the cavity. Just a few more inches and he will be inside the sound activation area. Just a few more inches. But suddenly he stopped. I had to do something. I had to get Zor moving again!

DOCTOR: Your power is broken, Zor. The Pescaton civilisation is at an end. Within hours, all that will remain of your planet will lie scattered across the universe.
ZOR: Correction. This is no end for we Pescatons, Doctor, only the beginning.

A few more inches. I must draw him forward a few more inches. But something is happening to me. I, I can't move. The eyes. The creature's eyes. Staring into me, right into me. I, I can't hold on. Falling away. My power is falling away.

ZOR: Only the beginning, Doctor. The beginning. Kill. Kill. Kill.
DOCTOR: The cavity. Inside the cavity. The switch!

(The tone starts, and rises in pitch.)

The sound tore into the creature's brain cells. It's whole gigantic body quivered and trembled. It's heart beat faster and faster and faster.

(As the pitch gets higher, Zor's roars get louder, until)

Suddenly, it was all over. Before my very eyes, the invincible, the all-powerful Zor, completely disintegrated. And with him, the entire species of an evil alien civilisation. All that remained now was the vertebrae of a giant deep sea fish. The lifeline was broken, the invasion at an end. So too was the planet of Pesca.

(Rumbles then explosions.)

And so, my friends, our story is at an end. The TARDIS is waiting and I must move on to another time, another place. Perhaps some remote corner of the outer universe. But whereever it is, we shall meet again. We shall meet again. Goodbye.

Transcript originally provided by Chrissie. Adapted by TARDIS.guide. The transcripts are for educational and entertainment purposes only. All other copyrights property of their respective holders.