'What else can I do? General Cutler holds all the cards. He makes the decisions.'

Polly looked around her for a moment, then leant forward across the desk, and whispered, 'Can't we wait, though-fight off the Cybermen until Mondas is destroyed? It might mean the end of Cutler's son, of course, but it would be one life against millions.'

The tall physicist looked at her miserably and shook his head. 'What can I do? If I don't follow the General's orders, he's quite capable of going ahead without me. He's a very ruthless man.'

'Couldn't we pretend to follow his orders-but make sure the rocket doesn't go off!'

Barclay looked at her with fresh hope, the idea beginning to take root... Suddenly, they heard Cutler's voice on the other side of the tracking room.

Polly moved back rather too quickly, as if caught in a conspiracy. But Cutler didn't seem to have noticed. He was speaking to the radar technician. 'Anything to report?'

'Yes, sir. A signal on the screen-about here.' He indicated with his finger. 'Fifteen hundred miles north north-east, alt.i.tude fifteen zero. It's been stationary for the last ten minutes.'

Cutler peered at the screen for a moment. 'Keep a close watch on it. Report to me the instant it starts moving. Any more word from my son?'

Barclay came to the General's side. 'We can't seem to raise him, General.'

'What?' His eyes searched for the R/T technician but, before he could speak, the radar technician broke in urgently: 'That blip, it's moving, sir. Coming in fast, course o-one-five.'

Where's it heading?'

'Straight in here, General.'

'The Cybermen again?' asked Barclay.

Cutler nodded: 'Must be.'

'Do we use the anti-missile battery this time?' asked Barclay. Cutler shook his head. 'No, I've a better idea. We'll let them land. Then ambush them with their own weapons.'

He looked towards the console by the door where the Cybermen's captured weapons were still laid out in a row, then tapped the R/T man on the shoulder. 'Put the whole base on red alert. Stand-by.'

'Right, General.' The R/T technician leant forward and spoke into the mike. 'Now hear this. All base to red alert stand-by. Repeat, all base to red alert stand-by. Enemy landing imminent. Report to your stations.'

Cutler picked up the phone and dialled a number. 'Security Major? Put your three best marksmen under snow camouflage and issue them with the captured Cyberweapons.

Report on your R/Ts when you are in position.'

Cutler turned back to Barclay. 'How long to count down?'

Barclay glanced at his watch for a moment. 'Ten minutes.'

'They'll be here by then. We'll have to hold them off first, then proceed with the launching.'

A buzzer sounded harshly. 'Well?'

Dyson's voice came over the loudspeaker system. 'The bomb's in position in the rocket, sir. Will you check it now?'

'Yeah, just got time before the battle commences.' He turned and strode rapidly out of the room.

Polly turned excitedly to Barclay. 'Now's our chance,' she whispered.

'What?' Barclay turned, startled.

'To see Ben-he may be able to help. We must do something to stop that rocket.'

Barclay hesitated, glancing indecisively from Polly to his seat at the control console.

'Quick,' continued Polly. 'It's our only chance-while the General's out of the room.

Come on-hurry before it's too late.'

Trying to appear inconspicuous, she picked up the coffee tray and walked towards the door. Barclay hesitated for just a moment and then followed her.

In the cabin, Ben had removed the grille and edged his body half way up through the exposed ventilation shaft. 'Lucky we don't get much grub on the TARDIS -I'd never get through this on navy rations ! '

Suddenly, he heard the cabin door open. Legs waving wildly, he tried to wriggle out of the shaft.

'Ben!'

He turned quickly: to his relief it was Polly!

She ran across and peered into the Doctor's face. He still seemed to be fast asleep. 'How is he, Ben?'

Ben eased himself down from the top bunk. 'Cor, I'm glad to see you, Polly.' He nodded towards the Doctor: 'He seems pretty fair.'

Barclay entered the room and closed the door behind him and Ben turned quickly, on his guard.

'It's all right, Ben, Dr Barclay's going to help us.'

'Great! Good work, Polly. What can we do to stop this rocket, then?'

Barclay looked towards the door, and then moved closer to the two time travellers.

'It can be immobilised quite simply-if one can get into the rocket silo, that is.'

'Can't you?'

Barclay shook his head. 'Cutler suspects me already. It's under constant guard. If I or any of my staff try to tamper with the controls, we'd be discovered immediately.'

'Is there any other way then?' asked Ben.

'I don't know.' Suddenly, he caught sight of the open ventilation shaft, and then looked down at Ben. 'Can you get through that?'

Ben nodded. 'I was just about to scarper when you came in. What about it?'

'I designed this part of the base. That's the main ventilation shaft. It leads through to the silo room-and the bomb ! '

Ben nodded. 'I get you. Maybe I could do something. Would I need a radiation suit?'

'No, the silo room is screened.' He thought for a moment. 'But there's a guard outside and there's sure to be an engineer or two checking the systems inside.'

'Couldn't we distract them?' queried Polly. 'Get them outside somehow?'

Barclay nodded. 'Yes, perhaps.'

Waah ! Waaah ! The harsh bray of the station alarm, sounding similar to a submarine alert, echoed through the base. Polly jumped. 'What's happened?'

'The Cybermen must have landed. I must go.' Barclay turned to the door.

'No,' pleaded Polly. She grasped his arm. 'Don't you see, this is your chance?'

Barclay thought for a moment, and then sat down again. 'You're right. Here.' He motioned to Ben and, turning to the desk, picked up a pencil and pulled a sheet of paper towards him. 'This is what you'll have to do.'

Ben watched as Barclay started to draw a plan on the graph paper. He glanced down at the tool kit which Ben had used earlier on the door. 'You'll need these.' He pointed to a section of his diagram. 'Unscrew this panel. Inside there are four small plugs.

Take out any of them, snip off a pin, and put it back.'

'What will that do?' queried Ben.

'The fuel pump pressure will drop to zero at blast off.'

'You mean the rocket engine won't work? But won't they spot it? And correct it?'

Barclay shook his head. 'Not in six months. That's not the sort of fault they would look for.'

Outside on the Polar surface; the wind had dropped, the moon had come out and a strange, unearthly silence dominated the crackling, cold landscape. The moonlight added a silver sheen to the Antarctic plains, giving them a dreamlike, shimmering appearance.

The long, ugly, torpedo-like shape of the Cybermen's s.p.a.cecraft broke the silence as it gently came to rest.

A moment later, the revolving red light began to fade, a slight whirring noise was heard, and part of the side section slid back. The first of the Cybermen stepped gingerly down into the Polar snows.

He looked around him, weapon at the ready-but all that was visible were the slopes leading up to the small cl.u.s.ter of chimneys and slight hump that marked the Polar base.

On the far side of the base, the Cyberman noticed the small, square shape of the TARDIS, and for a moment levelled his weapon in that direction-but there was no visible movement.

Rea.s.sured, he turned and pressed a signal b.u.t.ton on his chest unit. One by one, the other Cybermen climbed down from the s.p.a.cecraft.

At the entrance to the Polar base, the three guards detailed to ambush the Cybermen were waiting, rod-like Cyberweapons at the ready. They had made a rough 'blind' out of the snow with a white tarpaulin cover. With the exception of a small slit, they were completely invisible.

They watched as the Cybermen advanced across the snow.

In all, the guards counted twelve of the silver monsters, their tall figures glinting in the moonlight as they tramped in perfect unison through the dry powdery snow towards the base.

Nearer and nearer they came. In spite of the intense cold, the two men on either side of the Security Major were sweating with tension. When would he give the order to fire? There was something implacable and terrible in the steady, machine-like tread of the Cybermen...

The leading Cybermen had now marched to within ten feet of the blind.

'FIRE!' the Major shouted to his men. Almost simultaneously, the rattle of the three Cyberweapons rang out. The guards chosen for the duty were the three crack shots on the base-but it was unnecessary at such close range.

The three leading Cybermen jerked up their arms, staggered backwards, and fell.

Behind them, the other Cybermen looked wildly around for their opponents.

Again, the three guards fired with unerring accuracy.

Three more Cybermen dropped.

The other Cybermen, still unsure where the attack was coming from, began to retreat.

Again the guards fired at the retreating figures, and three more Cybermen jack-knifed into the snow.

The remaining three turned and ran wildly through the snow back towards their waiting s.p.a.cecraft.

The guards fired again, but the distance, and the strange ghostly Polar moonlight seemed to confuse them. Only one of the three remaining Cybermen was. .h.i.t. The other two reached the safety of the s.p.a.cecraft.

The Security Major flung off the white cover of the blind. 'O.K. Get their weapons.

Then back inside-fast!'

While the Major clambered down into the base to report, the other two men walked quickly over to the dead Cybermen to collect their prizes. One of the Cybermen had fallen on top of his weapon. Nervously, the guard kicked the lifeless giant aside, and s.n.a.t.c.hed up his booty.

Ben, inch by effortful inch, was heaving himself along the base ventilation system.

The shaft, a narrow, square tunnel with protruding metal joins, dug into him as he wormed his way along. Every few feet, the tunnel was dimly lit by a shaft of light which penetrated a grille. Ben wondered how visible he was through these close-mesh grilles, and made every effort to pa.s.s them as quickly as possible. His clothing had torn on the projecting screws, and his elbows and knees were raw and bleeding.