They might not see us.'

As he finished speaking, the first of the aliens appeared. They stopped for a moment, twisting their heads around in a not-quite-human way.

Then they all turned at once to face the squad and began to run down the slope towards them.

Twenty-Seven.

Mike Yates took Vincent's pulse again and slowly shook his head.

The man wasn't going to make it. Even if by some miracle a helicopter turned up now, chock-full of paramedics, he doubted they would be able to save Vincent. He'd lost too much blood.

Yates stared out at the desert. The horizon was already beginning to shimmer in the heat. He was going to have to start to think about water soon, and about getting out of the sun. He supposed that some of the Kebirians they'd left twitching aimlessly near the ruins of the nest would have supplies, but going there would bring its own problems. A seemingly endless chain of Xarax helicopters flew to the nest and returned, as Jo had said they would, carrying glistening globes of honey. Since the first wave, none of them had come too near to the road, but Yates didn't want to risk attracting their attention.

A harsh whisper interrupted his thoughts: Vincent. He turned, saw the man's eyes roll to meet his. The whisper came again: 'Leave me.'

Yates bent down over the man, shook his head. 'No.'

'Not till I die, eh?' Vincent's lips twitched in the echo of a smile.

'Don't be -' The voice stopped. For a moment Yates thought Vincent was dead, but then his eyes rolled again and he said, 'No need.' Then, amazingly, he tried to push himself upright.

'Take it easy,' said Yates, but Vincent shook his head.

'Look out, father,' he said. 'The Israelis are coming.' Then he flopped back on the ground with a bubbling sigh.

Yates leaned forward once more, to see if he was still breathing, but then heard the faint sound of rotor blades behind him. He whirled, saw a Xarax helicopter approaching, legs flush against its body, tail raised to sting, tentacles trailing from its belly.

He reached for his revolver, cursed Zalloua when he remembered it wasn't there. He glanced at Vincent, still not sure if the man was alive or dead. Cursing again under his breath, he crouched down and lifted him over his shoulder. The body flopped limply.

He slid off the road, almost fell down the slope into the gully. Then he walked along until he found an overhang large enough to give him cover.

He heard the whickering sound of the Xarax helicopter, and a strange booming like a huge heart beating. A curtain of tentacles trailed past the overhang, missing his skin by inches.

The creature seemed to hover for hours. Twice it moved away from the overhang, only to return; Mike wondered if it could smell him.

At last it went away, the whickering rotors slowly I fading into silence.

Mike looked down at Vincent, saw that his eyes had glazed over.

Dead.

Did I kill him by moving him? thought Mike; then shook his head.

No point in worrying about that now. He closed Vincent's eyes, muttered, 'Rest in peace.'

Then he started wondering what he should do next.

The Brigadier stared in amazement over the sloping armour of the tank as they pulled up alongside the perimeter fence of the air base.

The two UNIT Hercules transports were drawn up on the runway; American fighters moved between them. Moroccan soldiers were rushing forward, shouting and waving their arms.

'It's Al Haraf!' the Brigadier shouted down for Rashid's benefit.

'How the d.i.c.kens did you get us here, Doctor?'

'Quite simple, Brigadier,' said the Doctor, climbing up beside him, 'I cut through the Wadi Mazami, across the Bor-el-Duba and down the side of the Al Gol hills. Just look at the map: it's perfectly clear.'

By now the tank was surrounded by soldiers, all cheering and clapping as if the brigade had returned from a major victory instead of having turned tail and run. Somewhere behind them the Brigadier was relieved to see the familiar English uniform of Sergeant Osgood.

He clambered down the side of the tank, pushed his way through the crush to the Sergeant. Osgood caught sight of him and saluted.

'Everything all right, Sergeant?' said the Brigadier, briskly returning the salute. But he could tell from the expression on the man's face that everything was far from all right.

'We've got a few problems, sir.' He paused as two of the American fighters thundered overhead. 'The Americans have put through a request for a nuclear strike on Kebir City. They seem to reckon its been taken over by aliens.' Osgood sounded doubtful, which the Brigadier himself would probably have been if he hadn't seen what he'd just seen in Kebiria. 'And it's the same with Rabat, sir. We can't reach them. There's something about dancing.' Osgood sounded even more doubtful.

'Dancing the code?' asked the Brigadier.

Osgood nodded. 'That's what's on the radio from Rabat, sir. But it doesn't make any sense.'

'Well, it won't, will it?' The Doctor's voice. 'And what was that about a nuclear strike?'

Osgood repeated his information.

'That's utter lunacy! It's the worst thing they could possibly do! - Brigadier, we've got to get in touch with the US government at once and put a stop to this. If they use nuclear weapons in these circ.u.mstances it could quite literally mean the end of the world.'

The Brigadier frowned, turned to the Doctor. 'I agree that it seems a bit drastic,' he said. 'But surely it would work - there wouldn't be much left of the Xarax after an H-bomb went off on their doorstep.'

'Oh, really Brigadier,' said the Doctor. 'That's a typical military att.i.tude. Try to think, just for a change. We use helicopters - the Xarax imitate them. We use jets against the Xarax - the Xarax imitate them. What do you think will happen if we use nuclear weapons?'

The Brigadier thought for a moment.

'Well, I suppose they might -' He swallowed. 'Oh, I see.'

'Precisely, Brigadier. They only need to disable one warhead on its way in and they'll have the perfect model - and a supply of fissile material. Now get me a direct line to the President of the United States -' He broke off as two more of the American jets roared overhead. 'Before it's too late!'

'We're going to see the Queen,' said Sadeq Zalloua.

He'd said that several times, starting the moment when the concrete towers of Kebir City had first become visible through the heat shimmer on the horizon. He said it with a sure smile, a smile of such little-boy intensity that it scared Jo almost more than the gun pressed against the back of her neck.

They were well into the city now. The roads were littered with smashed cars, broken gla.s.s and other debris. Jo was having to pick her way between it all; twice they'd had to go back and take a different route. Zalloua wouldn't tell her where the Queen was: Jo wondered if he actually knew.

'What are we going to do when we get to the Queen?' she asked.

'I will take control of the Xarax. I will ensure that they carry out my program. They're not intelligent, you see.'

'Yes, the Doctor said that.' Jo stared out of the windscreen, slowed down as she saw the back of a truck projecting across the road. The front of the truck had smashed into a wall. As they drew closer, she could see a thick trail of blood leading from the truck towards a low, red-brick building.

Jo thought she saw something move behind the door of the building.

'Are you sure they'll let you take control?' she asked Zalloua, steering the jeep onto the pavement away from the wreck. 'I mean, the Xarax might not need you any more.'

'They will know who I am.' Zalloua treated her to another of his unnerving smiles.

There was definitely something moving; a human figure. A figure in a uniform.

A policeman.

Jo heaved a sigh of relief. Being arrested she could cope with.

Unless of course - She saw two more figures emerge from the building, begin to strut in line across the road. The way they moved was too regular, too clockwork for real people, even policemen. They had to be Xarax copies.

She steered back onto the road, heedless of the pieces of broken gla.s.s there. Stepped on the accelerator.

'Stop!' said Zalloua, jabbing the gun into Jo's neck. 'I have told you - they will know who I am. They will take us to the Queen.'

Jo drove on.

'STOP!' yelled Zalloua. 'I will kill you if you don't stop!'

Jo stopped the jeep, suddenly, with a screech of tyres. She became aware that her body was shaking.

'They won't know you, Monsieur Zalloua,' she said. 'They won't know anything. They're not intelligent. You said so yourself.'

The 'policemen' were only yards away now. Zalloua stood up in his seat, turned to them and said, 'I am Sadeq Zalloua.'

But the 'policemen' continued to advance. Jo, who had expected it, braced herself to run. Zalloua, who obviously hadn't, only repeated his statement, adding, 'I am your leader.' He was waving the gun around in the air, obviously no longer concerned with Jo.

She opened the door of the jeep, half jumped, half fell out. Zalloua, startled, shouted something and then fired his revolver. The bullet flew off the concrete surface somewhere near Jo's feet. She didn't stop running.

Then Zalloua screamed.

Jo didn't look over her shoulder to see why. She just ran on, blindly dodging cars, leaping over the trunk of a fallen palm tree. She ran until she couldn't run any more, until she collapsed against the side of a car, gasping, sweat pouring down her face. Only then did she look back.

The street was empty, except for the wreckage of cars. For a moment she thought that she saw movement at the limit of her vision; then she realized that it was just the heat shimmer over the concrete.

I must have lost them, she thought. She felt a wave of pure relief.

Then she realized that she was on her own, in a strange city controlled by aliens. She had no idea whether there were any other humans alive in the city, and if there were, she had no idea where they might be. The Doctor had talked about disabling the nest; she didn't know where the nest was, or where the Xarax queen might be, or how to disable it.

'What am I going to do now, Doctor?' she muttered aloud.

There was no reply.

'... honey honey good good sweet sweet honey dancing ... code honey dancing ... '

The voice on the radio went on and on, repeating its incomprehensible message. The words had an inflection that was robotic, repet.i.tive, barely human.

'And that's Rabat, you say?' the Brigadier asked, wiping the sweat and the flies from his forehead. The flies whirled up and away, began to orbit the slowly turning fan on the ceiling of the office.

Captain Oakley nodded. 'Even the Air Traffic control is out. Your pilot's going to have to fly by wire until you get across the Mediterranean.' The American Marine leaned forward, his hands pressing down onto the thick scatter of papers that covered the surface of his desk. 'Look, sir, I appreciate your position, and I am fully aware of the potential seriousness of the situation should we choose a nuclear option. But the facts are these. Kebir City is out.

Rabat is out. Giltat is out. There's some kind of trouble in Algiers, and there's been an air raid in Malta. That's a radius of five hundred miles, Brigadier. They're getting more planes up all the time - and it's getting harder to shoot them down. They're learning.'

'But don't you see, that's precisely the problem!' interrupted the Doctor, whirling around from the back of the office where he had been apparently inspecting the notice board. 'I've explained to you - '.

The Captain raised a hand. 'As I've said, Doctor, I understand your position. But I have my orders.'

'Then let me speak to the person who gave you the orders! Let me speak to the President!'

'I don't have a line to the President, sir. Only Admiral Carver on the Eisenhower Eisenhower has the authority to speak directly to the White House.' has the authority to speak directly to the White House.'

'You're saying that you've been told what to do but you've got no means of - '

The Brigadier decided that it was time to stop this argument before any more time was wasted. He knew the Doctor well enough to know that he wouldn't give in; and he suspected that Captain Oakley wouldn't either. He stepped forward in front of the Doctor, held up his hand.

'How long can you give us, Captain?' he asked.