'Fingers crossed,' Jack said. 'Well done.'

Sergeyev nodded, which seemed to be as close as he would come to congratulating his comrade.

'Right, let's get back to the inst.i.tute and see who's checked in. We can't do much more till morning and this mist burns off.'

'If it does,' Sergeyev said glumly.

'Oh, you're a bundle of joy,' Jack told him.

Sergeyev scowled back.

Razul was smiling with amus.e.m.e.nt at their antagonism. But his smile froze as he tossed the oily rag into a corner. 'What was that?'

'What?' Jack asked.

'A sound. Just then. Listen.'

They all stood silently, listening. There was a scuffling, sc.r.a.ping sound from behind the generator, barely audible above its steady throb of power.

'It's nothing,' Sergeyev said. 'Just the machinery.'

'Or rats, maybe,' Jack suggested.

But Razul was not convinced. 'It sounded like something outside, on the hull. Sliding across the outer sh.e.l.l of the submarine.'

Sergeyev gave a dismissive laugh. 'That's not possible,' he said. 'We are below the waterline.'

Vahlen took some persuading to leave his distraught wife and bring his digger to the graveyard. He glared at Minin, refusing point blank to talk to the man, and so the Doctor had to work his charm.

It only went so far before the Doctor lost his patience. 'Will you stop feeling so sorry for yourself and do something to help?' he demanded. 'Pavel's gone, and I'm sorry. But if you want to prevent anyone else having to suffer what you're going through, then I suggest you get off your backside and give us a hand.' He took a deep breath before continuing more quietly, 'There's something going on here that's wrong and dangerous. You know that. Everyone knows that. You ignore it or give it a mythical name because you think you can't stop it. But now that's got to change. It's time to make a stand. I can stop it. I will will stop it. But I need your help. All right?' stop it. But I need your help. All right?'

The huge mechanical shovel bit into the frosted earth. It struggled to penetrate, the main body of the digger lifting off the ground. But then it cut through suddenly, the digger thumping back down as the shovel came up. Its arm swung round, dropping the dark earth onto the snowy ground. Tendrils of mist played round the scene, the exhaust from the digger thickening the air.

The older graves had proper headstones: all identical, all arranged evenly in neat rows like soldiers on parade. But the more recent ones were marked by small wooden crosses and positioned haphazardly across the landscape.

'He was the last to die under similar circ.u.mstances,' Minin said as they watched the pile of earth growing. 'He's been in the ground for two years. You sure you want to do this, Doctor?'

'Why doesn't he like you?' the Doctor said in reply. doesn't he like you?' the Doctor said in reply.

'As you said, no one likes me.'

'Yeah. But he really really doesn't like you.' doesn't like you.'

The digger backed away. It drew level with Minin and the Doctor, and Vahlen leaned out of the cab. He spoke to the Doctor, ignoring Minin altogether.

'The casket's exposed now. You do what you have to. I'll get out of your way and fill it in again when you're done. I'd rather no one else knew about this.' The engine revved and the digger lurched forwards again. Then it stopped and Vahlen's head reappeared. 'You'll stop this? You'll make sure it doesn't ever happen again?'

The Doctor nodded. 'It might take a while. There may be some cost. But I'll stop it. Promise.'

Vahlen's head disappeared back into the cab, then the digger disappeared back into the mist.

'He used to work with a man called Chedakin,' Minin said.

They walked slowly across to the open grave. The Doctor had a spade over his shoulder. They looked down into the blackness.

'They were the best of friends. But Chedakin had a big mouth.'

'Careless talk costs lives,' the Doctor said.

'It cost him his, certainly.'

'Tell me.'

'They found him with a gun in his hand and a hole in the back of his head. Shot himself rather than be recalled to Moscow to explain his actions. That's the theory.'

'Suicide?'

Minin nodded.

'And Vahlen and the others blame you for that?' The Doctor jumped down into the grave. 'People are so short*sighted, aren't they,' he said. 'Right, let's get the lid off this coffin.'

The cold of the ground had helped preserve the wood and it took the combined efforts of the Doctor and Minin to lever the top from the plain wooden box that served as a coffin. Immediately, the stench from inside made them both gag.

'Well, we know he's still here,' the Doctor said.

Minin had a handkerchief clamped over his nose and mouth. 'Quick as you can,' he said, his voice m.u.f.fled. 'Let's get this over with.'

They wrenched the lid away and looked inside.

The coffin was empty.

'He's gone! Then where's the smell coming from?' Minin said.

The Doctor was stooped down beside the coffin. He had a test tube in one hand and a metal spatula from Catherine's lab in the other. 'He's still here, I'm afraid.' The Doctor was scooping something up from the bottom of the coffin and sc.r.a.ping it into the test tube. He stuck a rubber bung in the top and handed it to Minin. 'Hang on to this a mo.'

'What is it?'

'The clothes have rotted, probably an accelerated process. As with the body. Whatever did it drained the binding energy from everything, not just the bone and cartilage.' He tapped the test tube that Minin was now holding. 'That's what's left of the body.'

Minin stared at it in horrified disbelief. Inside was what looked like a lump of pale, colourless jelly. 'This was once a person?'

The Doctor pushed the lid back on the coffin and hauled himself out of the grave. 'Yep.'

'But how can someone end up like this?'

'Dunno. But ' he reached down and helped Minin climb out to join him 'unless we find out soon, we might all end up the same way.' He took back the test tube and shoved it into his jacket pocket. 'Cheering thought, isn't it?' he said happily, waving through the mist for Vahlen to come and fill in the hole.

The sound of the generator was a gentle throbbing from behind them as they made their way back towards the main hatch. They had almost reached it when they heard the noise again. Slithering, sliding, sc.r.a.ping from somewhere up ahead.

'I don't like this,' Razul whispered. He checked his Geiger counter, but the reading was the same as ever.

'It's ahead of us,' Sergeyev said.

'It does sound as if it's inside the boat now,' Jack agreed. 'Must be some machinery, or something loose shifting as the sub moves in the water.'

'It isn't moving in the water,' Sergeyev pointed out.

'Clever clogs,' Jack muttered. 'OK, then,' he said out loud, 'let's get out of here as quick as we can, agreed?'

The other two nodded. The ladder up into the conning tower was just ahead of them now, the whole metal world lit in blood red as only the emergency lighting seemed to work.

Razul reached the ladder first. He reached out for it, then pulled his hand away. 'It's slippery,' he said in a hushed voice.

'It's just rusty, that's all,' Sergeyev said. He reached out to check, then he too pulled his hand away. 'No, it's... it's as if it's been smeared with oil or grease or something.'

'Something cold,' Razul agreed. 'Icy. But sticky.'

'It's the only way out,' Jack said quietly. 'Do we debate what's happened or leg it?'

They were all three cl.u.s.tered round the ladder now. Sergeyev shone his torch at the rungs in front of them. 'Colourless,' he said. He moved the torch up, and they could now all see that something clear and viscous was coating the ladder. The beam of light reached the top of the ladder, illuminating the open hatch. And with a cry of surprise and fear, Sergeyev dropped the torch.

A glowing tendril, like pale seaweed, dropped down towards them, thrashing across the bottom of the ladder.

'Come on!' Jack led the way, running from the pale, glowing, gelatinous ma.s.s of the creature that was oozing down the ladder behind them.

'We should have headed back for the generator,' Razul gasped.

'There is no way out back there either,' Sergeyev said.

'No. But up here, we heard...' His voice tailed off.

They slowed to a halt. Their faces were pale even in the red of the lights. From behind them came the slithering sound as the creature dragged itself after them down the main corridor.

And from up ahead they could all hear the same sound. Not an echo, but another of the creatures. 'We're trapped between two of them,' Jack realised.

'It's cold, it's foggy and there's nothing here,' Rose announced. She was standing with her arms folded, close to one of the stones on the top of the cliff.

In front of her, Sofia was shining her torch slowly round the stone circle. The upright monoliths stood like soldiers waiting for orders dark shapes wreathed with mist.

'Just a few minutes more,' Sofia said.

'Why? There's nothing.'

'I want to test a theory.'

'What theory?'

Sofia switched off the torch. Her pale face seemed to glow in the suffused light. The tendrils of thin mist that wrapped themselves round her made the woman seem wraith*like, ghostly, as she stepped towards Rose.

'This creature must be part of it. So the systems are starting up on their own, without intervention.'

'What are you talking about?'

'I'm talking about a problem. My problem. It may all be coming to an end. I must know.'

Rose took a step back, away from the advancing woman. 'You're mental,' she muttered.

'And if the systems are activating themselves, then these stones will also be active all the time.'

'Active what do you mean? What do they do?' Rose was seriously spooked now.

Sofia's face seemed as old as weathered rock as she took another step forwards. Then she suddenly lunged at Rose and grabbed her wrist, pulling her.

'Don't you know?' she hissed, her face close to Rose's. She seemed suddenly much older than Rose had thought. Then she turned Rose round, so she was facing the nearest stone just a metre away.

'When they are active, when we turn them on, the stones drain the energy from anyone who touches them. They take it all, anything that can nourish and feed them. And leave just the empty skin.'

She shoved Rose away from her, holding her by the hair, forcing her face towards the stone.

SEVEN.

There was a faint tingling sensation on her cheek, like static electricity. Rose pressed back, trying desperately not to let her face touch the stone. But inch by inch Sofia was forcing her head forwards, both hands tangled in Rose's hair as she pushed. Rose grabbed the woman's coat, tried to push her away, but there was no way she could stop her.

So she didn't try. She let her legs collapse beneath her, falling suddenly downwards rather than forwards. Her face was still perilously close to the smooth, cold stone, but as Rose fell Sofia cried out in alarm and surprise. Her hands were wrenched from Rose's head. Rose twisted as she dropped down, determined to stay away from the stone. At the same time she kept hold of Sofia's coat, trying to pull her down as well downwards and forwards.

As Rose twisted, she saw Sofia crash into the stone. Crawling away through the churned*up snow, she heard Sofia's shriek of pain and fear watched her stagger back, hands over her face as if burned.

Rose didn't wait to see what the damage was. She was struggling to her feet, slipping in the slush, stumbling forwards towards the car.

She wrenched open the door and hurled herself inside. The door slammed shut, and a moment later Sofia was there, dragging it open again. Rose held on tight, let it open enough that she could slam it shut again, and pushed the handle across to lock it. Please don't let her have the key, she thought.

The key was still in the ignition. With a sob of relief, Rose turned it. The engine creaked and coughed but didn't start. She turned the key again.

And the windscreen cracked.

Sofia was kneeling on the bonnet of the car, hammering at the windscreen with the b.u.t.t of her torch. Another crack with each blow. Another couple of goes and it would break. The woman's face was a snarl of rage as she raised the torch in both hands like a dagger, preparing to strike again.