'You'll get used to it.'

They reached the door that Henry said led into the research area. It was locked, and there was no sign of a guard.

'There should be someone,' Henry said. 'At the main gate they said we needed Sir Manning's permission to get in.'

The Doctor agreed, and set to work with his sonic screwdriver. Soon he had the door open.

Once inside, they saw why there was no guard. Half a dozen men in dark uniforms lay sprawled across the floor.

From their wounds, the Doctor could tell they had been killed by the Krillitanes.

'They don't care any more,' the Doctor said sadly. 'The project must be even closer to completion than I thought.'

'But where are they?' Henry whispered.

The research area took up only a small part of the huge factory, but there were a few offices as well as the main workshop s.p.a.ce. Ma.s.sive metal tanks rose to the high ceiling. The Doctor tapped the side of one, and checked the displays on the pipes and tubes.

'It's full,' he told Henry. 'Nutrients and acids. The stuff of life. This is where it all happens inside this tank.'

'Are we too late, then?'

'Oh no. The new Krillitane bodies must be nearly ready, but they will still need to program the creatures' brains. They need to load character and behaviour, the way the creatures think and how they act.' The Doctor grinned and explained his plan.

Henry led the way to one of the small offices, and tuned on the computer. 'I don't know if I can get into the systems we need. This is the firm's internal website.' He pointed to the screen. 'It's already going haywire as the internet breaks down under the pressure of the Krillitane code. Look, the canteen menu says it's serving DNA with Custard for pudding today.'

The firm's online diaries were scrolling pages of Krillitane code. The Brainy_Crisps site didn't have the test any more.

Now it showed the weather forecast for the Shetland Isles.

Finally, between them, they got access to the factory's own online systems. If it all worked then Henry could control the whole output of the factory. He could change the amount of salt and oil in the crisps. He could get the systems to slice the potatoes thicker or thinner. He could even change the ingredients.

'Apple crisps might be nice,' the Doctor said. 'Or turnip.

What do you think, turnip? Maybe not. Just do what you can,'

the Doctor told Henry. 'I'm relying on you, Henry. The world is relying on you.'

'No pressure, then,' Henry muttered.

They both ducked down below the window as a shadow crossed it. A Krillitane was standing outside the office. They waited, then Henry breathed a long sigh of relief as the creature moved away at last. The Doctor let himself out of the room. He had another job to do.

The Doctor saw several Krillitanes as he crept through the factory. They were no longer in their human forms. That made them easier to spot, of course, but it was a worry that they were so confident.

A group of four of the creatures stood by one of the ma.s.sive tanks. The Doctor guessed they were waiting for the process to finish. It probably wouldn't be long now. When all the Krillitanes were looking the other way, he ran to the next of the tanks.

One of the Krillitanes turned as the Doctor hurried past.

Perhaps it caught sight of a blur of movement, a shadow moving across the floor. The Doctor took shelter behind the tank. It was an enormous steel drum.

The Doctor put his ear to the metal. Deep inside he could hear something moving. He could imagine the new breed of Krillitane creature thrashing in the liquids that gave it energy and life. The fluids that kept it fed and healthy as it grew.

He wondered what it would look like. Would it be like the Krillitanes now patrolling the factory? Or would it be very different? He knew that, unless he acted now, he would soon find out.

The Doctor found the main control valve. This was what fed Krillitane Oil and other nutrients into the tanks. He pulled out his sonic screwdriver and aimed it at the valve.

A clawed hand clamped down on the Doctor's shoulder.

It dug in, sharp and painful. Another claw knocked his sonic screwdriver aside.

The Krillitanes all looked very similar. But there was enough difference in their features and colour for the Doctor to recognise Sir Manning. Behind him, the Doctor could see Stella Sark and Gabby, watching him with hungry eyes.

'You really thought you could defeat us, Doctor?' Sir Manning said.

The Doctor pulled himself free of the painful grasp. He rubbed his shoulder and stretched. 'Careful, that hurt.'

'I'm so pleased.'

'Kill him,' Stella Sark said.

'Oh, don't I get to see the final product?' the Doctor complained. 'You said yourself, I can't defeat you now. Why don't you let me live a bit longer. At least then you can have a decent gloat. How did you find me, anyway?'

'We guessed you would come,' Gabby said.

'You see, Doctor,' Sir Manning added, 'you are so very predictable. In a few moments you will indeed witness our victory. Before you die.'

Chapter Eleven.

'Well, I hope it's worth it all,' the Doctor said. 'I mean, hijacking the internet and making all those crisps.' He could see patches of dark burned skin on Sir Manning and Miss Sark. 'I hope there's no lasting damage, by the way.'

Miss Sark hissed with anger. 'We should kill you now.

Why wait?'

'Well, that's right,' the Doctor agreed. 'You're keeping me alive so I can witness your big success. Only, what if it isn't such a big success? What if it all turns out to be a bit rubbish? That would be such a waste of effort. Not to say embarra.s.sing.'

The Krillitane that was Gabby stepped forward. Her claws clicked on the concrete floor, sending up sparks. 'Why did he come here?' she asked. 'What was his plan? He still seems very sure of himself. What can he have done?'

The Sir Manning Krillitane hurried over to the valves and pipes where the Doctor had been working.

'It seems we found you just in time. You were going to open the main flow valve from the oil feed,' he guessed.

'Oh, someone's getting clever. Been at those Brainy Crisps, have we?'

'If he had opened this main valve,' Sir Manning explained to the other Krillitanes, 'the oil would have gushed out of its tank. It would have spread through the whole place.'

'Highly inflammable cooking oil flooding the building.' The Doctor smiled. 'Sounds like a recipe for disaster, if you ask me.'

'You should show some respect,' Miss Sark snapped.

'Your only hope is gone. What is it they say? You win some, you lose some.'

'No,' the Doctor replied. 'Well, yes, they do say that. But it's not true. Not in my case. You see, I win them all.'

'It's over, Doctor,' Sir Manning said. 'You and your stupid friend...' His voice tailed off and the creature swung round.

'Where's Henry?' he demanded.

'Ah, sorry. He had to go home. Wasn't feeling too good.'

The Doctor patted his pockets. 'I've got a sick note somewhere...'

'He's here,' Gabby realised. 'Henry is still hiding here in the factory.'

'Find him!' Sir Manning ordered.

Gabby hurried away, her wings beating urgently. Sir Manning turned back to the Doctor. 'Where is Henry? What is he doing?'

The Doctor sighed, and made a point of brushing dust off his lapel. 'You made the same mistake as Gabby.'

'What mistake is that?' Miss Sark asked.

'You undervalued Henry. Just like you've undervalued all the humans on this planet. You're going to pay for that.

Unless you leave now.' The Doctor's eyes were hard, his face grave. 'I don't usually give another last chance. You don't know how lucky you are. Leave now, while you can.'

They did not laugh at the Doctor's words this time. Sir Manning turned his large head towards Miss Sark. 'Find Henry. Get all the brothers and sisters to search. We are so close, we cannot be denied our destiny now.'

Henry was feeling pleased with himself. He had at last managed to log into the factory systems. They were messed up by the problems with the internet, but he thought he could find a way to do what the Doctor wanted.

His biggest challenge was to stay safe. More than once, Krillitanes walked past the office and he had to duck out of sight, but he was soon absorbed in his task.

In fact, he was so absorbed that he didn't notice the door swing open. A shadow fell across the desk.

'Be with you in a minute,' Henry said, out of habit. He was used to people waiting to talk to him while he worked in his office.

Except he wasn't in his office, he remembered.

Nervously, Henry looked up.

A Krillitane was looming over him. With a snarl of rage, it reached over the top of the desk. It grabbed Henry's shoulders. He felt the claws pierce his jacket and his shirt.

Then the Krillitane hauled him up from the chair.

Clamped hard against the creature's bony chest, Henry could not move. The creature snarled with glee, and dragged him away.

Sir manning's alien eyes narrowed as he watched the Doctor.

There were just the two of them now, standing between the giant metal tanks.

'You're too clever to be caught so easily,' said Sir Manning.

The Doctor grinned at him. 'You're so kind. But no, you caught me fair and square, so well done, you.'

'You came here on purpose. You knew that the most obvious action you could take against us would involve the oil.' Sir Manning looked up at one of the huge metal tanks beside them. 'There is enough Krillitane Oil in that tank to destroy this whole factory. Because of the way the process works, it has to be right next to the birth-tank. That is where the new Krillitanes are being created.' He turned to gesture at the tank on the other side of them. 'As I say, it was an obvious target.'

'There you are, then.'

' Too Too obvious. You were certain to fail, and you knew that.' obvious. You were certain to fail, and you knew that.'

'Perhaps I'm not as clever as you look.'

'Or perhaps that was not really your plan at all. You lured us here while Henry did the real work. Tell me, Doctor what has he been doing? Where is he?'

The Doctor met Sir Manning's gaze. 'Henry will stop you.

Be sure of it.'

There was a cackle of alien laughter from behind him.

The Doctor spun round and saw Krillitane Gabby drag Henry round from the other side of the tank.

'Not so clever after all,' she said. She pushed Henry away from her, and he stumbled and fell.

The Doctor helped Henry to his feet. ''Did you do it?' he whispered urgently.

Before Henry could answer, Sir Manning pulled the Doctor away.

'You see, Doctor, you simply cannot win. Your friend failed. In moments now the final data will finish flowing into the new Krillitanes. A race will be born. A new race of Krillitanes that will conquer the universe. We have won!'

From the huge metal drum that Sir Manning had called the birth-tank came a sound. It was a sc.r.a.ping, scratching sound. Then a m.u.f.fled boom.

It was the sound of the creatures inside trying to get out.

Chapter Twelve.

Henry and the Doctor stood next to the birth-tank. Stella Sark checked the gauges and readouts.