'What happened to her?' Rose wondered.

The Doctor and Jack leaned Valeria against the stone where Sofia had been. Jack was breathing heavily.

'Same as happened to the boy, Pavel, I'd say. Only a less extreme dose,' the Doctor guessed.

'What could do this?' Jack asked.

By way of reply, the Doctor turned towards Sofia. 'What do you think?'

She shrugged. 'Some disease or infection.'

'Yeah, right.' The Doctor nodded. 'And what do you really really think?' think?'

The woman turned and held his gaze. 'Vourdulak,' she said. Then she gave a snort of anger and waved her hand dismissively. 'What do I know?'

'You'll come with us to the inst.i.tute,' Levin told her.

'If I must.'

'I can't make you,' he said. 'But I am asking.'

'Very well. But I shall drive.'

She walked over to the car and opened the driver's door. After a moment, the soldier sitting there got out.

'Let's get her into the car,' the Doctor told Jack. 'Maybe they can help at this science base.'

'Or not.'

'So what did she mean by Vourdulak?' Rose said. 'Or is it just me who's confused here?'

'The Vourdulak is a creature from Russian folklore,' the Doctor explained. 'It's a vampire that takes the form of a beautiful young woman, though it's really an ancient and evil monster.'

Rose held open the back door of the car as Jack helped the girl inside. Valeria's wrinkled face still showed no expression, her eyes still stared sightlessly ahead.

'So, what? She reckons the poor girl was got by this vampire thing?'

Jack didn't reply. He climbed into the back beside Valeria.

'Am I missing something here?' Rose demanded.

The Doctor led her a few steps away from the car. 'Or it could be she thinks the poor girl is the vampire thing.'

There was a medical unit at the base, but no doctor.

'There's only the four of us now,' the Head of Projects explained. 'We're lucky if we can get sticking plaster, never mind staff.'

His name was Igor Klebanov and he was a short, dark*haired man who, despite his protestations about the lack of comforts, was tending towards stout.

All four of the staff were gathered in the small medical unit, evidently excited to have company. A tall man with thinning grey*streaked hair introduced himself as Alex Minin. 'I'm not a scientist,' he apologised. 'I stayed on to handle the admin side of things.'

'Not being a scientist, they didn't transfer poor Alex,' Klebanov put in. 'And Boris and Catherine are only here for two years as part of their university training.'

'Monkeying about,' Boris Brodsky said. He grinned as if it was a joke, and Rose saw that Alex Minin glared back at him, as if he was on the receiving end of it. Boris coughed and added, 'Two years is more than enough.' He was in his mid*twenties, with red hair and freckles, and he seemed unable to stop grinning. 'I shan't be upset to leave. I don't know why you you stayed.' This was to Klebanov, but again Rose felt there was a dig at Minin. stayed.' This was to Klebanov, but again Rose felt there was a dig at Minin.

'I don't like to leave things unfinished. I was here during the Cold War years,' Klebanov explained to the newcomers. 'I was chief scientist when the base was all but closed down.'

'You must have been very young,' the Doctor said.

'Perhaps I am older than you think?'

'P'raps we all are,' the Doctor joked.

Bored with the male banter, Rose stepped aside to chat to the only woman on the base. Catherine Kornilova told her that she was a mature student, studying for a higher degree in nuclear physics.

'So you're quite at home here with the submarines and stuff,' Rose guessed.

The woman smiled thinly. 'Quite the opposite. I know how dangerous it is. Like Boris, I can't wait to leave. I just hope I can find another job. Otherwise I'll be stuck here like poor Alex.'

'Can't he just transfer somewhere else?'

'Maybe.' She shrugged. 'He was the political officer here. With that on his record, it's difficult. But I sometimes think it's even harder for him to stay.'

'Why?'

'Because everyone who was here back then everyone except me and Boris, I suppose they remember who he was and what he did. How he watched and reported everything. And they hate him for it. Even Klebanov. Even Boris, I think.'

Rose looked across at Alex Minin, and found that he was looking back at her. For a moment their eyes met, then the tall man looked away, running his hand through his thinning hair to make it seem as if he wasn't watching them at all.

'Right, then,' the Doctor announced, clapping his hands together. 'Everyone out. I need a bit of peace and quiet to examine the patient and the body.'

That jolted Rose. Talking to Catherine, she had almost forgotten there was a dead body under a sheet on the other side of the room. And a young woman whose mind had been emptied and her body aged, sitting silent and helpless beside the corpse.

Levin gestured for the few of his men who were with them to leave. Most he had already sent to patrol the village or guard the base, though against what threat no one asked. Others were helping themselves to equipment from the base stores.

Sergeyev paused on his way out. He looked over at Jack, standing beside Valeria. 'I guess the captain likes older women,' he said to the soldier beside him. They both laughed and turned to go.

But Jack was across the room in a moment, grabbing Sergeyev's shoulder and turning him round. His eyes were blazing angry.

'Sir?' Sergeyev said. 'I a.s.sume I call you "sir", even though you are in Intelligence.'

The mockery in his voice was plain, and the room was suddenly silent around them. Rose swallowed, hoping Jack would let it go, but knowing he wouldn't.

'Yes, you call me "sir",' Jack said, his tone dangerously controlled. 'And you show some respect.'

Sergeyev smiled. He glanced round checking Levin was nowhere to be seen, Rose guessed. 'Oh, I'm scared, sir.

Jack smiled back. But the smile didn't reach his eyes. 'Know what scares me?'

'Everything, sir sir?'

Jack ignored him. 'I used to think I was scared by death. Or by facing death by combat and action and the uncertainty of the battlefield. Not any more. No, now what scares me is the possibility I might live to grow old. I might wake up one day tired and wasted and unable even to open a beer. I might need crutches and a hearing aid and help getting dressed. When and if I get to that point, it'll be my memories that'll keep me going. The fact that I've lived through so much, survived so much, to get there. Do you want to get old?' he asked, prodding Sergeyev in the chest. 'Do you want to end up with only your memories to make up for the loss of your faculties?' He pointed across the room. 'Look at her. Look! She's there already. Nineteen, and she can barely walk on her own. She should be looking forward to her whole life, not staring at the end of it and wondering what happened. If she can wonder at all.'

Sergeyev didn't reply.

Jack held his gaze for a moment more, then turned away. 'Get out,' he said. 'Go and do something useful, while you still can.'

There was an embarra.s.sed silence as the others slowly followed Sergeyev from the room. Klebanov paused to clap his hand on Jack's shoulder, as if to say he understood.

'Help yourselves to whatever you need,' he told the Doctor. 'If you want anything else, talk to Alex and he'll do what he can.'

Soon only the Doctor, Rose and Jack were left. And Valeria.

The base had been built to house fifty scientists and their equipment. With just four, it was virtually empty. Levin found several large storerooms packed with filing cabinets, which, Alex Minin explained, contained all the records from when the base was fully operational and fully funded. Everything from payroll details to equipment requisitions and original schematics for building the place.

Minin had suggested the soldiers use the lecture hall as their base since it was the largest room. Levin took an office on the same corridor as his headquarters. Not that he'd got anything to put there apart from his pack. But he had Minin bring him pads of paper and pencils and a large*scale map of the area.

The Doctor found him half an hour later.

'You're finished?' Levin said, waving for the Doctor to sit down opposite the desk. 'That was quick.'

'I'm not a medical man. Just a quick examination.'

'So you can tell me nothing.'

'I can tell you why there are no biros,' the Doctor said, nodding at the pencil that Levin was tapping on his fingers. 'The ink freezes in winter.'

'Then I'm glad it's only autumn. I intend to be long gone by the time winter arrives.'

'Think you'll have finished?'

'I'm only here to investigate the energy spike. We find something, we're gone. We find nothing, we're gone. This death, that poor girl a separate matter.'

'You sure?'

'Aren't you?'

The Doctor leaned back and crossed his legs. He was an odd one, Levin thought, not for the first time. If the phones worked he'd call Moscow and get some background on him. But his paperwork seemed in excellent order. Someone must think highly of him. So Levin said, 'Tell me.'

'The dead kid jellified. As we thought.'

'That's hardly a medical term.'

'But it's accurate. All the energy drained from the body and the bones dissolved. The calcium seems to have been sucked out or something. Same with the girl, only to a lesser extent. I'd guess her bones are weakened and brittle. But the process is less far gone. Something interrupted it.'

'But what caused it?'

'Thought you weren't interested.'

'Not professionally.'

'Then you should be.'

'Oh, yes?'

'Oh, yes. Think about it. The energy was sucked out of those kids.'

Levin was getting bored with this. 'So?'

'So...' The Doctor uncrossed his legs and leaned forwards. 'Ask yourself. Where did it go?'

And now Levin did see. 'That energy spike? But surely there's not enough energy in two human bodies one and a half, actually to show up like that?'

'No, there isn't.'

'So that wasn't the source.'

'Not all of it, no. There must be something else.'

'As I said, another unrelated source.' Levin leaned back, to show the matter was closed.

'Possibly. But it might not be instead, it might be as well. Something we haven't found yet.'

Levin felt cold even colder than he did already. 'Like...'

The Doctor was nodding encouragingly.

'Like more bodies,' Levin said.

There were two Jeeps, or the rather clunky Russian equivalents, at the base. Jack demanded a driver to take him and Valeria to her home in the village. He specifically asked for Sergeyev, though he wasn't sure why he'd done that.

He was sorry to admit to himself that if he was honest he'd be glad to get rid of the girl. OK, he felt sorry for her no one should have to go through whatever she'd been through. But it wasn't as if she knew anything about it. Her hurting was done and there was nothing that Jack could do now. Best get her home and let her parents worry about it and sort her out.

Maybe he wanted Sergeyev to see him dust his hands of her, to see he was one of lads really. Then Levin had agreed that Jack would help organise the group taking readings with their Geiger counters and stuff. Intelligence officer was an easy role, he decided, as he sat in the back of the Jeep with the motionless girl.

Sofia Barinska agreed to drop the Doctor off at the stone circle.

'I just want to have a look,' he said. 'And Rose wants to see the village, don't you, Rose?'

'Do I?'