DOCTOR WHO AND THE INVISIBLE ENEMY

by Terrance Dicks

  'No, not yet,' commanded the Nucleus.

  Apparently, it felt that a quick death was too good for the Doctor. 'We shall take him with us to Titan—to be consumed by the Swarm!'

  10

  The Antidote

  Leela looked admiringly at herself in the mirror set into the locker door. She'd broken open a first-aid locker in the reception area, and was using a random assortment of ointments and dressings to produce a fair approximation of someone in the first stages of virus infection. A nurse's robe she found hanging in another locker completed her disguise. 'How do I look, K9?'

  'Friend, Mistress,' said K9, failing to understand her question.

  Leela checked the blaster hidden under her robe. 'If I can just get close enough to that Nucleus, it'll see how friendly I am.'

  'Hostiles approaching, Mistress,' warned K9. 'With the Doctor.'

  They ducked into a doorway for cover.

  An extraordinary procession was coming down the main corridor. First came the heaving, pulsating Nucleus, its breath gurgling liquidly in its throat. Lowe and a medic were supporting it between them. Behind them came the Doctor, firmly strapped down to a hospital trolley, pushed by Marius.

  The Nucleus was growing impatient. 'Hurry! Hurry! It is time for the spawning. I must go to the place prepared on Titan.'

  From the corner of his eye Marius caught sight of Leela's uniform. 'Nurse, take over here. I must assist with the Nucleus!

  Hesitantly Leela came forward. Marius showed no signs of recognising her, perhaps because of her disguise, perhaps because personality meant little to those who served the Purpose. Marius let Leela take over the pushing of the trolley, while he went to help Lowe and the others with the cumbersome, constantly complaining Nucleus.

  The Doctor looked up. 'Your eye make-up's running, Leela! ' he whispered.

  'Ssh! ' reproved Leela. She slipped the knife from under her coat and began sawing at the Doctor's bonds.

  By the time they reached the TARDIS, standing forgotten in its corner, the Doctor was free.

  With a sudden shove, Leela whizzed the trolley towards the TARDIS door.

  Marius turned. 'Nurse, not that way!'

  But it was too late. The Doctor sprang from the trolley, opened the TARDIS door and leaped inside. K9, who had been lurking behind the TARDIS, whizzed round to the front and followed the Doctor in. Hampered by the cumbersome Nucleus, it took Lowe and Marius too long to react. Lowe detached himself from the group and raised his blaster. Leela fired a quick blast at random. It missed, but it was enough to spoil Lowe's aim. The blaster-bolt sizzled harmlessly over her head, and seconds later she was safe inside the TARDIS with the others. The door closed behind her.

  'They have escaped,' screamed Lowe.

  'They are trapped,' corrected the Nucleus. 'Without its missing component. the Doctor's craft cannot move. Marius, you will stay here, to make sure the Doctor does not escape. Recruit other host bodies. When the Doctor emerges, recapture him, and join us on Titan.'

  Marius bowed his head in assent.

  Lowe and the others carried the Nucleus towards the airlock. A Foundation shuttle craft stood fuelled and ready in the departure bay. Soon the Nucleus would be on Titan, and the spawning could begin.

  Thankfully Leela peeled off the last of her disguise. 'Well, Doctor, now what?'

  'Now nothing,' said the Doctor gloomily. He was watching the airlock door on the scanner, as it closed behind the Nucleus and its attendants.

  'Doctor, if we can get to Titan first we can still beat that horrible thing.'

  'Well, we can't. The dimensional stabiliser's still in the isolation ward. Without it the TARDIS won't move an inch.'

  'So there's nothing we can do?' asked Leela disgustedly.

  'Did I say that, K9?' The Doctor looked down. K9 was gliding inquisitively round the TARDIS control room, pausing to sniff, or rather to sense, various interesting pieces of equipment. 'Listen to me, K9! Do you think you could go out there and poleaxe Marius?'

  K9 said 'Query: please clarify term "poleaxe".'

  'Knock him out!'

  'Affirmative. My weaponry has four levels of intensity. Kill, stun, paralyse...

  'No, no, no, not kill. Just knock him out, eh?'

  'Affirmative.'

  'Good dog! '

  The Doctor looked at the scanner screen. After hovering indecisively for some time, Marius was heading for the reception desk.

  'Off you go then, K9.' He opened the TARDIS door and K9 glided out.

  Marius was at the reception desk microphone. 'All senior staff to reception. This is Professor Marius. Senior staff to reception...' He looked down coldly as K9 approached. With the virus now controlling his mind, Marius could no longer understand the streak of sentiment that had caused him to want a computer in the shape of a dog. 'K9,' he said coldly, 'I no longer need you.'

  K9 blasted him, and Marius slumped to the ground. The Doctor and Leela rushed from the TARDIS, picked up Marius, threw him on to the trolley that had been used for the Doctor, and whizzed him away.

  The trolley sped along the corridors and shot into the isolation ward. The Doctor burst into a flurry of activity. He took a blood sample from his own finger, mounted it on a slide, then turned to Leela. 'Your turn, Leela, finger! Quickly, we haven't got a moment to spare.'

  Leela winced as the Doctor pricked her finger with the little scalpel.

  The Doctor smiled. 'Come on, Leela, not frightened of a spot of blood are you—mighty hunter! '

  'Just hurry up,' said Leela, sucking her finger.

  The Doctor mounted Leela's blood sample next to his own and slid the slide into the computerised electron microscope. Leela watched him, baffled. 'Haven't we been through all this before?'

  'I had the virus then—I'm immune now. Something must have happened while you and I were inside my head. I want to find out what!' The Doctor switched on the microscope's read-out screen and studied it absorbedly. 'Ah, now that's very interesting.'

  Leela looked at the swarming patterns on the screen, her blood sample and the Doctor's side by side. To Leela they looked completely different—but not to the Doctor.

  He leaned forward and tapped the screen. 'See that fish-hook shape wriggling about? That's an antibody, the only one you and I have in common. I didn't have that before, so it must be the immunity factor.'

  'How did what I have get into your blood?'

  'Quite simple. Your clone. which was produced from your tissue, was absorbed into my bloodstream and passed on the immunity to me. All we've got to do is isolate it, analyse it, duplicate it, and inject it into Marius here, and he in turn will be able to cure all the others.'

  Leela couldn't believe things were quite that simple. 'What about the Nucleus? What about Titan?'

  'One thing at a time, Leela,' said the Doctor reproachfully. 'One thing at a time!'

  The Foundation shuttle, sides marked with the red cross, was carrying its strange passengers towards Titan. Lowe was at the controls, while the Nucleus was pulsating on an acceleration couch, surrounded and supported by its taken-over aides. 'Faster, faster!' roared the Nucleus. It was in a slavering frenzy of impatience.

  'We can't,' said Lowe. 'Any faster and the motors will burn out.'

  'Let them burn out. Once we reach Titan and the breeding tanks, your task is finished.'

  'What about the Doctor?'

  'He will follow us to Titan, a prisoner. Marius will make sure of that. Faster, now. Use all the fuel! Faster!'

  Obediently Lowe thrust the speed-control lever to maximum. The shuttle surged forward with a roar that shook the little cabin.

  The Doctor and Leela hovered anxiously over Professor Marius. He had been injected with the antidote some time ago. Now they were waiting to see the results.

  'It's working,' whispered Leela. 'Look, Doctor!'

  With incredible speed the virus rash was receding from Marius's face. Soon it was completely back to normal.

  'Sometimes my brilliance astoni
shes even me,' murmured the Doctor modestly. 'Come on, Marius, wake up, wake up!

  Marius opened his eyes and peered blearily at them. 'What happened?' He sat up and looked round. 'Where's Parsons?'

  'Dead, I'm afraid. Do you remember anything?' Marius frowned. 'I remember Lowe coming in. then there was a flash... then nothing... Doctor, did the experiment work?'

  'Yes—and no,' said the Doctor ruefully. 'Unfortunately, the Nucleus got away, and the dimensional stabiliser increased it to human size. It's on its way to Titan to breed.'

  'And was I taken over?' Marius rubbed a hand over his face, relieved to find it normal.

  'Yes, it got you, for a while, Professor. But we've found the immunity factor. So we're safe here, at least for the time being...'

  Marius was overjoyed. 'The immunity factor? What was it?'

  'It was something in Leela, something we all missed.' He handed Marius a phial of milky liquid. 'This is the antidote, but you'll have to make a great deal more. And Professor, if those antibodies can confer immunity, they can be developed to attack the Nucleus! '

  'Attack the Nucleus?' said Marius, alarmed. 'That will be highly dangerous, Doctor.'

  'Of course it's dangerous! But if we allow the Nucleus to breed and swarm, it will go through the entire galaxy like a plague of giant locusts.'

  'But even if we develop a way to destroy the virus, will you be able to get it to Titan on time?'

  'Yes!' said the Doctor triumphantly. He crossed to the booth and picked up the complex electronic equipment. 'Now I've got this back, we can use the TARDIS...'

  The huge bubbling tank was completely walled-in, the only entrance by a heavy metal door.

  Safran looked through the thick plasti-glass viewing window set into the door. The giant tank was filled with a bubbling, seething fluid. He studied a control panel beside the door. Temperature, nutrients, atmosphere, all were exactly right.

  With a smile of pride, Safran crossed to a space-radio set up in the corner and leaned over the speaker-microphone. 'Safran on Titan. Safran on Titan. The Hive is prepared. The breeding tanks are ready. Temperature and humidity are set.'

  Safran glanced back proudly at the seething, glowing tank. 'I await your arrival—and the generation of the Swarm!'

  The entire control cabin was shuddering with the speed of the shuttle's flight. But still the Nucleus was not satisfied. 'Faster, faster!' it screamed.

  'There is no more I can do,' shouted Lowe helplessly. 'We have already reached maximum speed!'

  'We must go faster, Lowe,' it roared. 'The time for spawning is very close...'

  The shuttle sped on. As soon as it arrived on Titan, mankind would be doomed...

  11

  The Hive

  The isolation ward was a scene of bustling activity again. Leela, the Doctor and K9 had been scouring the Foundation for infected medics, knocking them out, and dragging them back to the isolation ward where they were forcibly injected with the antidote. When a sufficient number of medics had been cured, they were set to work manufacturing supplies of the antidote and sent out in teams to cure their fellow workers. It would be a long time before everything was back to normal, but slowly the Foundation was coming back to life.

  Leela had quite enjoyed that part of the proceedings, but now she was restless again. The Doctor and Marius were busily trying to produce a killer-virus that would destroy the Nucleus and its Swarm. It seemed to be a very long and complicated business, and Leela soon grew tired of watching masked and robed medics bustling about with dishes of virus-culture.

  'How much longer, Doctor?' she asked impatiently.

  The Doctor was absorbed in his work. 'Can't rush these things, they're breeding them as fast as they can. K9's linked to the computer-microscope. He'll tell us when we've got the most powerful strain.'

  Leela brooded for a while. 'Why don't we just blow up Titan?' she suggested cheerfully. 'Nucleus, breeding tanks and all! '

  The Doctor looked reprovingly at her. 'That's your answer to everything, isn't it? Knock it on the head!'

  'Well, it's effective, isn't it? Smash it, once and for all...'

  'With what?' demanded the Doctor. 'This happens to be a hospital, not an arsenal!'

  'All right,' said Leela sulkily. 'How are you going to fight it?'

  K9 bustled forward importantly. 'Confirm strain C531 has optimum lethal capacity.'

  Marius hurried up to them, in a state of great excitement. 'Doctor, we've done it! Congratulations!' He turned to his assistants. 'Manufacture a batch of C531 immediately. Hurry now, there isn't a moment to be lost!'

  The Doctor leaned down and patted K9 on the head. 'Thank you,' he said solemnly.

  Leela was impatient. 'And now what?'

  'We just chuck it into the breeding tank, and wait for it to attack the Nucleus the same way the virus attacked us... microscopically! Neat, don't you think?'

  'Oh, is that all?' asked Leela satirically. 'If we can get to Titan in time, if we can get past Lowe and the others, if it works when we finally let it into the breeding tank ' She checked herself. 'I thought you didn't like killing?'

  'I don't.'

  'Then why are you doing all this?' asked Leela, confident she'd caught the Doctor out for once.

  'The virus has a perfect right to exist as a virus—but not as a giant swarm threatening the galaxy. Everything has its place. Otherwise the delicate balance of the whole cosmos is destroyed!'

  'I still say we should blow it up,' muttered Leela sulkily.

  Marius came hurrying forward, holding a vacuum-container. 'Doctor, the batch is complete!'

  The Doctor took the container in his hands, and stood looking down at it for a moment. 'Good! Now for the TARDIS!'

  The Nucleus emerged from the airlock on Titan Base and moved slowly and painfully along the corridors, assisted by its solicitous helpers.

  Safran stood waiting at the door of the giant fuel tank. Proudly he opened the hatch and the Nucleus heaved itself to the brim of the tank. 'Remember,' said the gurgling voice, 'I must be protected while I am in the Hive. The future of the Swarm depends on you!'

  Lowe and Safran and the aides bowed their heads in reverence. The Nucleus disappeared into the seething tank of nutrient.

  Safran stepped back, and closed the door reverently. The breeding of the Swarm was about to begin.

  The Doctor and Leela paused by the open door of the TARDIS to say good-bye to Marius and K9. 'Good luck, Doctor,' said Marius.

  'Thank you.' The Doctor turned to enter the TARDIS and then paused. 'Oh Professor?'

  'Yes?'

  'I don't suppose we could borrow K9, could we?' asked the Doctor hopefully.

  'Borrow K9—what for?'

  'I've got used to having him around—and he can be very useful.'

  'Of course, I understand.' Marius looked down. 'K9! Obey the Doctor.'

  'Affirmative,' said K9 happily, and disappeared into the TARDIS.

  Marius stepped back, the TARDIS door closed and a few minutes later there was a strange, wheezing, groaning sound. The TARDIS disappeared. Marius blinked in mild surprise, and then hurried away. There was still a great deal to do before the Foundation could be got back to normal.

  Lowe moved along the gloomy, winding corridors of Titan Base, followed by his medics. All were armed with blasters, and Lowe posted a guard at each main intersection.

  When he was satisfied his defences were complete he returned to the great fuel tank and looked through the viewing window.

  The Nucleus lay inert, pulsating gently in a sea of bubbling grey jelly. Surrounding it were thousands upon thousands of eggs, round and white, as big as tennis balls. They lay floating on the seething tank of jelly awaiting the moment when it was time for them to hatch...

  By means of a rather nifty feat of navigation, the Doctor managed to materialise the TARDIS in Supervisor Lowe's office. The visiphone screen showed the interior of the breeding tank. The Doctor studied the seething mass of eggs. 'The breeding season's
already under way!

  Leela stared at the screen in alarm. 'Doctor, what is it?'

  'It's the Swarm—and it's starting to hatch. We must hurry!'

  The Doctor looked out of the office door, and then stepped back.

  'What's the matter?' whispered Leela.

  'There's a guard coming. He must have heard the TARDIS...'

  Leela motioned to the Doctor to step back, and waited, drawing her blaster.

  'Come in! ' shouted the Doctor cheerfully.

  The guard stepped through the door, blaster at the ready. Leela fired. The guard staggered back. Incredibly he didn't fall, even though he'd been shot at point-blank range. Slowly, painfully, he raised his blaster to cover Leela. She fired again but there was no effect. It wasn't until K9 glided forward and added his blaster-fire to her own that the guard staggered, and finally fell.

  'Thank you, K9,' said Leela. 'Doctor, what went wrong? Why didn't my blaster work?'

  The Doctor was kneeling by the fallen guard. The man was in an advanced stage of viral infection, face and hands almost covered by the growth of stiff, metallic hair. 'Their internal cell structure must be changing. They're developing a resistance to radiation—'

  'Master, I have a problem,' K9 broke in suddenly.

  'Offensive capability seriously diminished, reserves... very low.' K9's eye-screen went dim, all his antennae drooped, and he became very still.

  'K9's breaking up, my blaster's finished,' said Leela worriedly. 'Doctor, what are we going to do?'

  'Shall we try using our intelligence?'

  'Well, if you think that's a good idea,' said Leela dubiously.

  The Doctor was already disappearing down the corridor. 'Come on,' he shouted. 'And you, K9.'

  Leela ran after the Doctor and K9 glided after them.

  They hadn't got very far before they carne to another intersection—and another guard. They flattened themselves back against the wall, and the Doctor whispered, 'K9, you see that guard?'

  'Affirmative.'

  'I want you to decoy him.'

  K9 glided into view. The astonished guard stared for a moment and then raised his blaster. K9 zig-zagged wildly, the blaster-bolts missed, and K9 vanished down the corridor with the guard in pursuit.