'You'd better be right about this, Doctor,' he said.

The Doctor turned to him and smiled.

'Trust me, old chap,' he said. 'I know exactly what I'm doing.'

Sixteen.

'Look, Doctor, are you all right?' asked the Brigadier.

The Doctor made his usual response to questions of that kind: in other words, he ignored it, and carried on with what he was doing. He had got the large retort down from its stand - the one the Brigadier had always imagined was in the UNIT lab purely for decoration, or possibly to give the cleaners something extra to dust. Now it was filled with a reddish-brown fluid, in which bobbed a brown object about the size of a ping-pong ball. The fluid was, in the true alchemical tradition, boiling, though the Brigadier could see no obvious source of heat. The lab smelled sweet, spicy, rather like that perfume Jo had been wearing on the flight.

He glanced across at Jo. 'Is he all right, Miss Grant? You haven't even told me what happened to you in Kebiria.'

'We didn't come to any harm, Brigadier,' said the Doctor without looking up. 'I can a.s.sure you of that.'

The Brigadier brushed his uniform down with his hands, looked at the floor for a moment. 'Good. I'm glad to hear it.' He hesitated.

'Look, we've got a bit of a problem with Kebiria and I think you might be able to help.'

'Problem?' The Doctor prodded at the retort, then looked up and smiled. 'Brigadier, Kebiria's problems are over. It's the rest of the world we have to worry about.' He returned his attention to his experiment.

'I'm afraid not, Doctor. We can't raise Kebir City on the radio or the telephone; the Foreign Office has apparently lost contact with its emba.s.sy staff there; the American emba.s.sy made a call for help about an hour ago, then lost contact.'

The Doctor looked up sharply. 'Are the Americans doing anything about it?'

'They're moving some ships into the area, but as for finding out what's going on - that's up to us. I've already been on to North Africa HQ in Rabat and they're providing some men.'

'Good, good. You take whatever steps you think are necessary, Brigadier. Keep me informed, won't you?'

'Frankly, Doctor, I was hoping you would have some suggestions.'

'The only suggestion I can make, Brigadier, is that you leave me to get on with this vitally important experiment in peace in peace.' The Doctor returned his attention to the retort. The object floating inside it was noticeably bigger than it had been when the Brigadier had come in.

The Brigadier swallowed, glanced at Jo, hoping for sympathy; but the young woman didn't move, just stared at the Doctor's experiment.

Suddenly she seemed to notice the Brigadier's gaze and jerked into life.

'That's right,' she said. 'The experiment has to be finished before we can do anything else.'

The Brigadier frowned, stared at his boots. Something was wrong.

The Doctor's behaviour was no more irritating than usual: but Jo was acting - well, not like herself. She moved like Jo, she spoke like Jo, but she didn't behave like Jo. Jo would have been concerned about what was happening in Kebiria. Jo would have questioned the Doctor, asked why the experiment was so important. She wouldn't just have taken it for granted that he was right. It was almost as if - An icy thought trickled into his brain. He remembered the cold, soldierly expression on his face when he had killed Jo. He would have to do that - he would have to kill both of them - if - He swallowed again, hard. It was nonsense, he told himself. Of course he wouldn't have to shoot them. Of course they hadn't been taken over by aliens. The Doctor was far too canny for that. No, he was just being his usual infuriating self: and Jo - well, perhaps she was feeling a bit off colour.

He decided to make one last try at communication. 'Is there anything that you need me to do? Shall I order up ma.s.s production facilities for this -' he gestured at the bubbling fluid in the retort '- this antidote, or whatever it is?'

'No, Brigadier, that won't be necessary,' said the Doctor. 'We have all we need here.' He was lifting the retort carefully off its stand, shaking it to and fro slowly. The liquid inside frothed and churned.

'Now if you'll excuse me, I really am very busy.'

The Brigadier shrugged his shoulders. That was a familiar enough line at least. 'All right, Doctor, have it your own way. I just hope you know what you're doing.'

'Of course I know what I'm doing, Brigadier. You can trust me.'

I hope so, thought the Brigadier as he left the lab. He was thinking of the locked drawer in his office, of the gun he had never thought he would use.

I really hope I can trust you, Doctor, he thought. I really do.

Private John Sh.o.r.egood looked out of the sentry box at the grey forecourt of UNIT HQ and wondered if Kublai Khan III would win.

If he did, Private Sh.o.r.egood would be quids in - five quid, to be precise. Which would come in handy. Even with UNIT bonuses a private soldier's salary didn't come to much, and Jenny was nagging at him for a new washing machine.

Well, every little bit helps, he thought.

He looked at the black telephone on the wall of the sentry box and wondered if he dare use it to ring Ladbrooke's. It was four-forty now: the race should be on any minute.

But even as he was thinking about it, he saw the familiar figure of the Doctor running across the courtyard, his cape flying in the wind.

He was shouting something, and the something was clearly aimed at Private Sh.o.r.egood.

Cursing inwardly, Sh.o.r.egood stepped out of the sentry box. 'What is it?'

'We need some help in the lab!' shouted the Doctor. 'An experiment has misfired rather badly, I'm afraid.'

Sh.o.r.egood frowned. 'The lab, Doctor? But I'm on sentry duty. I mean, I can't just leave - '

'It really is extremely urgent. Miss Grant is in danger.'

'Jo?' Sh.o.r.egood looked up at the main building, half expecting to see smoke coming out of the windows. But everything was quiet.

'What's the matter?'

'Quickly!' The Doctor seemed desperate.

Sh.o.r.egood glanced at the road. It was quiet. He picked up his walkie-talkie, pressed the 'send' b.u.t.ton.

'I'll have to get Ryman over to watch the gate,' he explained to the Doctor.

But the Doctor just shook his head. 'They've already got Ryman.

Quickly, man!' He set of at a run for the main building: Sh.o.r.egood followed, wondering who 'they' were.

Inside, everything was strangely quiet. The desk Sergeant was missing, there was no clicking of typewriters from the secretaries'

offices.

'Doctor?' asked Sh.o.r.egood. 'What's - '

But the Doctor was already running down the corridor that led to the lab. Once more Sh.o.r.egood followed.

The lab door was open. Inside Sh.o.r.egood saw a bench turned on its side, a uniformed figure lying across it with blood on his face.

A face that Sh.o.r.egood recognized. 'Ryman?'

The Doctor was already inside the lab, leaning over the injured man. Sh.o.r.egood raced in after him, saw something moving to his left.

He looked up, saw Jo Grant.

Jo Grant, standing on a chair - Jo Grant, with a hammer in her hands - A hammer that was moving down towards his head, moving so fast that there was no hope of - I don't believe it, thought Sh.o.r.egood. It isn't possible.

And that was the last thought that Private Sh.o.r.egood ever had.

I don't believe it, thought the Brigadier. It isn't possible.

The phone was ringing again.

The first opportunity he'd had to get some proper kip in almost two days and the phone was ringing. He wondered if he could get away with ignoring it.

No, it was too loud for that. And it wasn't going to stop.

He rolled off the bed, reached automatically for his trousers, realized he was already wearing them. And his green Army jersey.

And his Army boots.

I must have been tired, he thought.

The phone was still ringing. Wearily, the Brigadier reached out and picked it up.

'Lethbridge-Stewart speaking.'

'Brigadier, old chap, we've got a problem in the lab.' The Doctor's voice. 'Jo's in danger. You'll have to come over straight away.'

Seventeen.

Report, thought Catriona desperately. Observe. This is the story of a lifetime.

- the last story of my lifetime I'm never going to see the editorial the last story of my lifetime I'm never going to see the editorial office I'm never going to see London again office I'm never going to see London again - - Shut up, she told herself fiercely. Whining never got a reporter anywhere.

She parted her cracked lips, stared down at her swollen fingers.

'Catriona Talliser. Tape two.' There was no tape recorder, of course, but she could pretend, couldn't she?

- you can't pretend you're not dying you can't pretend you're not you can't pretend you're not dying you can't pretend you're not going to die like Deveraux going to die like Deveraux - - SHUT UP!.

'Tape two,' she said again. 'I'm in the - the nest, I suppose I have to call it, of an alien species, somewhere under the surface of Kebir City. There are perhaps a hundred of us in a dimly lit earth-lined chamber, and there must be many more people down here, judging by what I saw on the surface before I was kidnapped.' She broke off, thought about Jo, staring at her from the door of the Hercules, not recognizing her, denying her, betraying her. Why?

- honey honey sweet sweet honey honey sweet sweet - - She shook her head. No use thinking about that either. Now, where had she got to in her report?

She reached down to switch off her tape recorder and rewind it to find out, then remembered it wasn't really there. That she was really going to - - die I'm going to die someone save me someone please die I'm going to die someone save me someone please - - - honey honey good good sweet sweet dancing to be good to be honey honey good good sweet sweet dancing to be good to be honey honey - - SHUT UP!.

She swallowed, licked her cracked lips, remembered where she'd got to. 'I haven't seen enough to be sure, but it's entirely possible that the whole population of Kebir City has been captured. I don't know what they intend to do with us. I don't know -' She felt the panic rising again, tried to clench her fists, but her fingers were too swollen.

'We're all tied down - no, that's not quite right, we're attached to the walls - by rope-like tentacles. Most of the people here are unconscious, and the ones that aren't -' She swallowed, closed her eyes for a moment, then made herself carry on. 'I've tried to talk to the ones that are awake but they don't make much sense. They talk about - '

- honey honey sweet sweet honey honey sweet sweet - - '- honey and dancing, as if they were -' As if they were just like the insects, the mindless insects that had brought her down here.

- good to be honey to be sweet sweet dancing good to be honey to be sweet sweet dancing - - 'It's as if their minds had been destroyed - no, that's too strong - as if their minds had been suborned. Changed. Made alien.' But on the other hand, she thought, it was comforting. It helped, when you knew you were dying, to be - - sweet sweet honey dancing sweet sweet honey dancing - - - it was so easy to believe and so much - - sweet sweet good good sweet sweet good good - - - sweeter than being a reporter - - to be dancing to be honey to be good sweet to be dancing to be honey to be good sweet - - 'It's so much easier,' she said aloud. 'To be sweet to be honey dancing to be sweet sweet honey, to be dancing the code - '

- dancing the code dancing the code - - 'A whole city - a whole world -' It sounded wonderful, and yes so easy so sweet sweet sweet sweet, now that she didn't have to think any more.

- dancing the code dancing the code dancing the code dancing the code - - '- sweet sweet honey observe report honey sweet - '

- dancing the code dancing the code dancing the code dancing the code dancing the code dancing the code - -

The Brigadier stared at the locked door of the armoury and wondered why there wasn't anybody on duty. There wasn't anybody on duty anywhere in UNIT HQ. There wasn't a sentry on the gate; there wasn't a duty officer on the desk; and now there was no one in the armoury.

Something was wrong. Seriously wrong.