The Doctor ran along the corridors towards the Special Wing. 'Our best cell' could only mean the condemned cell, and that was close to the Process Chamber.

'Jo,' he called. 'Jo, are you there?'

In the condemned cell, Jo and Doctor Summers were listening at the door.

Jo looked up at Summers. 'I'm sure I heard gunfire.'

'Perhaps some of the prison officers are still holding out.'

'Either that, or the Doctor's arrived!'

They heard the Doctor's voice.

'Jo! Jo, are you there?'

Jo put her lips to the peephole in the door. 'Is that you, Doctor? We're here in the condemned cell.'

Faintly the Doctor heard Jo's voice. 'All right, Jo,' he called. 'I'm coming!'

Just as the Doctor was pa.s.sing the Process Chamber, Mailer appeared at the end of the corridor. He saw the Doctor, raised his rifle and fired.

The Doctor ducked, spun to one side, and shot through the open doors of the Process Chamber.

In the condemned cell, Jo heard the shot. 'Doctor,' she called. 'Doctor, are you all right?'

Silence.

In the Process Chamber all was dark and silent.

The squat, sinister bulk of the Keller Machine dominated the far end of the room. The Doctor took a few steps towards it.

A voice behind him said, 'I rather thought you'd make for here, Doctor.'

The Doctor turned and saw the Master stepping from behind the door.

'Did you now?' said the Doctor coolly.

Mailer ran through the doorway. At the sight of the Doctor, he raised his rifle...

'No, no, Mailer,' said the Master reprovingly. 'Give me that.' He took the rifle from Mailer's hands. 'Now, show our patient to the chair, and handcuff him in.'

The Doctor considered resistance, but the combination of Mailer, the Master and the loaded rifle was just too formidable. And as long as the Master wanted him alive...

The Doctor sat in the Keller Machine chair, and Mailer handcuffed his wrists together behind him.

Satisfied that the Doctor couldn't move, Mailer stepped back.

'Thank you, Mailer,' said the Master urbanely. 'Now then, Doctor, I've effected some necessary repairs and adjustments to the Machine, and I'm about to try an experiment. I believe you can resist the influence of my Machine at least for a time.'

'May I ask the purpose of this charade?'

'A test, Doctor, to see how long you can hold out.' The Master began searching the Doctor's pockets. 'Now, I'm sure you'll have it here somewhere... ah, good.' He produced the telepathic amplifier that the Doctor had taken from Chin Lee. 'This device, as you know, transmits and amplifies the power of the Machine. It can also be adjusted like this to turn that power against the wearer.'

Making a quick adjustment to the device, the Master slipped it behind the Doctor's ear.

The Master went over to the control console. 'You'd better get out, Mailer.'

Thankfully, Mailer left the room. For all his toughness, Harry Mailer was suddenly very scared. There was something about the Master which made him feel that his own criminal career was no more significant than the tantrums of a child.

The Master's hands moved over the controls, and the Keller Machine began throbbing with life.

The Master backed away. 'I should like to stay and witness your nightmares, Doctor.'

'Then why don't you?' taunted the Doctor.

'I have business elsewhere,' said the Master, and hurried from the room.

'Too scared to stay,' thought the Doctor, then winced as his mind was engulfed in a sudden wave of fear.

The box was throbbing with energy now, and its electronic pulsing shook the entire room.

First came the flames. The Doctor braced himself. The flames weren't real, the terror of the Inferno was past.

A huge-eyed reptilian snout swam towards him out of the fire. A Silurian... Instinctively the Doctor shrank back.

The Silurian faded and a Dalek swum towards him... its harsh metallic voice grating inside his head. ' Exterminate! Exterminate!

Exterminate! Exterminate! ' '

It too faded, only to be replaced by the tall silver form of a Cyberman... then a War Machine...

Monster after monster, terror after terror from the Doctor's past loomed up to attack him.

The Doctor could have dealt with any one of them, after all he'd met and defeated them all before... But the steady, unremitting parade of horrors, combined with the atmosphere of pure fear generated by the Machine was eventually too much even for the Doctor...

Suddenly panic overtook him. For a moment he writhed in vain against the bondage of the steel handcuffs then his body gave a convulsive jerk and his head fell back.

10.

The Mind Parasite The terror generated by the Keller Machine was spreading through the prison in waves.

The Master forced his way through a little group of escaped prisoners. They had dropped their weapons and were crouched on the floor, moaning with terror.

The Machine, the Master realised, was as big a menace to his allies as to his enemies. It had had to be controlled. It took all the strength of his ferociously determined will for the Master to force himself to return along the corridor to the Process Chamber. He lifted the bar on the door and went inside. to be controlled. It took all the strength of his ferociously determined will for the Master to force himself to return along the corridor to the Process Chamber. He lifted the bar on the door and went inside.

Once inside, the Machine was still pulsing with evil power. The Master hurried to the console and tried frantically to close it down. After a moment the electronic pulsing ceased...

He hurried over to the Doctor who lay slackly in his chair, head lolling back. The Master studied him for a moment with what looked curiously like concern. He s.n.a.t.c.hed up a stethoscope and listened to the Doctor's hearts. First the left one nothing. Then the right and here there was a feeble but steady beat.

The Master thumped the Doctor very hard on his chest, directly over the left hand heart. He thumped him a second time, and used the stethoscope to listen once more.

Now the left hand heart was beating too, slowly at first, then with increasing vigour.

Harry Mailer came cautiously into the room. Is he dead?'

'Not quite. You'd better wait outside.'

Mailer left.

The Master stood looking thoughtfully down at the Doctor.

The door to the condemned cell was flung open and Vosper beckoned to Doctor Summers. 'All right, you, out!

You're being transferred to another cell.'

'Why me? What about Miss Grant?'

'She stays here, lucky girl. Luxury cell, all to herself.'

Vosper nodded to the convict behind him. 'All right, Charlie, get him!'

Charlie, a burly, brutal type, grabbed Summers by the arm and dragged him out.

'I won't go without Miss Grant,' shouted Summers.

'Why don't you let us go back to the medical wing we could do some good there...'

His protests ignored, he was dragged off down the corridor.

Jo looked at Vosper. 'What's so special about me?'

'We're saving you for the Machine,' said Vosper, and slammed the door.

The Doctor stirred, moaned and opened his eyes to find the Master looking down at him.

'Doctor, Doctor welcome back! Would it surprise you to know that one of your hearts had actually stopped? You were within seconds of death.'

The Doctor's voice was so faint as to be almost inaudible. 'You wanted to find out if I could hold out against that thing. Well, the answer is, I can't. No one can.'

'If I can control it from the console, Doctor, so can you.'

'No,' whispered the Doctor. 'No...'

'Come now, Doctor, we are both Time Lords.'

'I know the secret of that Machine. Inside it there is an alien creature. A mind parasite. It feeds on the evil in the mind. Soon it will feed on the evil in yours.'

'Nonsense,' said the Master uneasily. 'We can control it we must!' He raised his voice, 'Mailer!'

Mailer reappeared in the doorway. 'Yeah?'

The Master nodded towards the Doctor. 'Release him and put him in the condemned cell with Miss Grant.' He leaned over the Doctor. 'Now, listen to me, Doctor. Unless you do as I ask, Miss Grant will be next in line for processing. All right, Mailer, take him out!'

Mailer unlocked the Doctor's handcuffs, and heaved him to his feet.

The Doctor was so feeble that Mailer had almost to carry him along the corridor to the condemned cell. 'Come on, Doctor,' he jeered. 'Your feet are dragging.'

Suddenly the Doctor rallied. Flinging Mailer aside he made a desperate attempt to escape.

Vosper, who had been waiting by the door of the condemned cell, darted forwards and clubbed the Doctor with his pistol.

As the Doctor fell, Mailer raised his rifle like a club for a second, savage blow. A voice snapped 'No!'

The Master was standing at the end of the corridor. 'I happen to need the Doctor in one piece. Put him in the cell!'

Vosper unlocked the cell door. Mailer heaved the Doctor to his feet and shoved him inside. He staggered a few paces forward, and then fell.

As Jo ran to help him, a familiar voice spoke from the doorway. 'Good evening, Miss Grant. A great pleasure to see you again.'

Jo turned round in astonishment. 'Master! What are you doing here?'

'The Doctor will explain when he recovers. Try to make him see reason, my dear for your own sake. Good night, Miss Grant.'

The Master stepped back, and the door closed behind him.

In the corridor, Mailer said, 'Why don't you turn him over to me and the boys? I'll have him eating out of your hand.'

'You don't know the Doctor. All you could do is kill him. I don't want him hurt just guarded. I want an armed man on this door at all times.'

Vosper nodded. 'All right. I'll do it meself.'

'Mailer, I want the Special Wing completely cleared except for those two in there.'