'You agree the claim's in jeopardy, then?' Bunny grumbled.

'Of course it's in b.l.o.o.d.y jeopardy. So let's see if we can turn this mess around and get that lex for ourselves.'

Bunny folded his arms. 'I'm still not happy about it.'

'I'm not asking you to be happy about it, you big lummox.

I'm asking you to help. OK?'

Bunny glowered at the holograph ring on his right middle finger. 'OK.'

'It seems fairly straightforward,' said the Doctor. Just a matter of finding the right access code now'

'Is that all?' Tegan asked heavily. They were sitting in front of the computer console. The monitor had filled up with glowing green letters and numbers and then blanked out on them. Tegan hadn't had much experience of computers on Earth, and tended to treat them with suspicion. Her cousin Colin had been a bit of a computer geek; she remembered a dreary afternoon spent playing Ping-Pong with him on his brand-new home computer. Colin had found it enthralling, and told her how computers were soon going to revolutionise the way the world worked and played. Some chance, Tegan had thought.

'Perhaps we should try hitting it again,' Nyssa suggested.

'Sarcasm isn't your strong point, Nyssa,' said the Doctor.

'Let's switch back to more conventional methods: try, tapping a few keys and see what happens.'

Nyssa sighed and started to work.

A terrible sound filled the air: a long, agonised shriek of mortal suffering. It was so unexpected, and so shockingly unnatural, that it took several seconds before anyone could properly identify the noise. At first, they did nothing but look at one another.

The scream suddenly died away, becoming little more than an expiring cough of air.

'Down there,' Nyssa pointed at the open portal to the lower chamber. The corpses' chamber. Tegan felt the hairs stiffen all over her body.

The Doctor looked quickly around the lab. 'Where's Vega Jaal? He was here a minute ago - oh, no...'

He whirled around and plunged through the doorway without any further hesitation.

The body was lying in the centre of the room, a little way from the others. The Doctor rushed over to Vega Jaal's withered remains and knelt down. His fingers gently touched the Vegan's face. The flesh was nothing more than dry, fibrous meat.

Bunny had followed the Doctor into the chamber and glanced quickly around. The corpses of the other victims still lay in the centre of the room, but the rest of the chamber was empty 'He's dead, I'm afraid,' the Doctor was saying, unnecessarily. Vega Jaal's once huge, liquid eyes were now blind, screwed up lumps of blackened tissue.

'Oh, dear Lord,' whispered Bunny. 'It must still be here.

Whatever it was that killed all those others... it's still here!' it's still here!'

They exited the lower chamber and shut the door behind them. For a few minutes they all stood in the main lab, agitation soon giving way for the need to blame.

'Who the h.e.l.l let him go down there on his own?' Bunny had demanded fiercely. The skin of his face was bleached with shock.

'I didn't even know he'd gone down there,' Tegan said.

'Someone must've seen him!'

'No one did, Bunny,' said Stoker. 'He must've slipped down there when we were busy.'

'But why?'

Stoker boiled over at this point. 'How the h.e.l.l should I know?'

'He was curious,' said the Doctor.

'Well he's dead, dead, now,' snapped Bunny. Then he sank into a chair and buried his face in his hands. 'Sorry' he said. 'I'm sorry.' now,' snapped Bunny. Then he sank into a chair and buried his face in his hands. 'Sorry' he said. 'I'm sorry.'

Tegan put a hand on his arm. She felt immensely sorry for him. All he wanted to do was go home, a feeling Tegan remembered only too well.

'Why did did Jaal go down there?' the Doctor was asking. Jaal go down there?' the Doctor was asking.

'What could he sense?'

It was Nyssa who spoke up in reply. 'Vega Jaal said there was another door. He said that every time we found a door, it led down into the darkness.'

'That's true enough,' Tegan muttered.

'He said the next door would be the last door,' Nyssa went on. 'And that beyond that there was nothing nothing but darkness.' but darkness.'

'I don't understand all these riddles,' protested Stoker.

'What does it matter, anyway? He's dead.'

The Doctor was pacing the room, without taking his eyes off the door. 'Vega Jaal knew there was something down there. Something dangerous'

Tegan frowned. 'And yet he still went down there?

Without telling anyone?'

'Yes, without telling anyone,' the Doctor repeated thoughtfully. 'Because he knew someone would try to stop him, or else go down there with him'

'd.a.m.n right,' Bunny confirmed.

'That could only mean he didn't want anyone else to share the danger,' Stoker said.

'He wanted to face it alone,' the Doctor agreed.

'Are you trying to say Vega Jaal went down there alone because he knew knew something would try to kill him?' asked Bunny. something would try to kill him?' asked Bunny.

'Yes, I think that's exactly what he did.

Tegan was aghast. 'But that's awful! Why would he commit suicide like that? It doesn't make sense!'

'It would to a Vegan,' the Doctor said. 'Jaal warned us that we were all going to die. He had already accepted his fate. Taking the initiative, confronting the probable cause of his death, would guarantee him a place in the Vegan afterlife.

And it would also serve as as a warning. To us.' a warning. To us.'

'He sacrificed himself?' Nyssa said. 'That's horrible.'

The Doctor shrugged. 'It's also academic, I'm afraid.

Vega Jaal has proved his point: there is is something deadly here, something with the power to drain a body of blood in a matter of seconds. He's alerted us something deadly here, something with the power to drain a body of blood in a matter of seconds. He's alerted us to to a very real danger.' a very real danger.'

'We shouldn't be staying here,' said Bunny. 'We should all move back up into the caverns. It's got to be safer.'

'There's no point in us all staying down here, I suppose,'

the Doctor agreed.

'Don't tell me you want want to stay?' said Stoker. She pointed at the wall, 'You're telling me there's some kind of killer on the other side of that. To me the next step is obvious: we should lock this place back up and seal it in.' to stay?' said Stoker. She pointed at the wall, 'You're telling me there's some kind of killer on the other side of that. To me the next step is obvious: we should lock this place back up and seal it in.'

The Doctor shook his head. 'We have to find out what it is. We can't leave until we do.'

Stoker looked to Bunny. 'What do you think?'

'I don't know any more, Jyl. I just don't know.'

'But we can still save the claim,' Stoker insisted. 'Seal this place up, blow it up, flatten it: I don't give a d.a.m.n. The sooner we get back to our proper job, the better. For all of us.'

Bunny banged his fist down on the bench top, denting it.

'Oh come on, Jyl - Vega Jaal's dead! We haven't even told the others yet. If we do anything now, it should be to pack up and leave. Forget the lex.'

'We can't leave until the ship gets here, you know that.'

'Then we send a mayday call. Interstellar. Someone's bound to pick it up.'

'Yeah - like the Consortium for starters' Stoker let out a hiss of despair. 'Can you just stop and think about this first, Bunny? I've got a claim to protect here. I don't want you going all jittery on me just because you're due some home leave!'

Bunny growled and stood up. 'Do what you want, you always do.'

As Bunny stalked out of the lab, Stoker suddenly jumped up and ran after him. She stopped at the doorway and bellowed after him,

'Don't you dare send that mayday, you b.a.s.t.a.r.d!' Her voice echoed back at her, full of desperate anger and fear.

She closed her eyes. 'Oh, h.e.l.l and d.a.m.nation.'

'I'll go after him,' said Tegan, brushing past. 'He's just upset, that's all.'

Stoker opened her eyes and looked wearily at the Doctor, who had sat down and put his feet up on one of the benches. 'Are you quite finished?' he asked pointedly.

'Don't get snappy with me, Doctor, I'm not in the mood.'

The Doctor swung his legs down. 'In case you're forgetting, Vega Jaal's body is still on the other side of that door. We have to get it back. We have to find out what killed him. We have to find out what is going on here.'

'What's all this "we" business?' Stoker said. She ran a hand over her head and leaned against the exit door. She felt extraordinarily tired and confused. 'I hadn't bargained on all this,' she added quietly.

Nyssa said, 'You cannot leave Vega Jaal's body down there.'

Stoker looked up at the wall where the secret door was.

It looked blank, innocent. She really didn't want to know what lay on the other side any more. But Stoker knew that Nyssa was right: she had a duty to Vega Jaal. 'OK,' she said. 'Let's do it.'

Vega Jaal was still screaming, even though he was dead.

It was soundless and without breath, but you could see it was a scream: his mouth was open, wide enough to see the shrivelled tongue inside. Sharp yellow teeth protruded from shrunken gums, the lips pulled right back by the harsh angle of the jaw.

Stoker swallowed back the bile in her throat and stepped closer to the corpse. Jaal's remains had been carried out of the lower chamber and placed on one of the workbenches in the main lab. Under the strip-lights he looked as yellow as parchment.

The Doctor was examining the body in minute detail.

Stoker fell she owed it to Vega Jaal to be present, but it was all she could do to stop herself throwing up. She wanted to look away, but she wouldn't allow herself that luxury. Jaal was dead. She was alive. What comfort did she deserve?

'Look at this,' said the Doctor. He was inspecting the side of Jaal's skull through his magnifying gla.s.s.