'It is is now,' said Stoker. now,' said Stoker.

The Dark twisted its head towards Stoker. She was standing right next to them, holding a gun. Through a scarlet haze the Doctor recognised it as Cadwell's DSA automatic.

The muzzle flashed and the Dark's head jerked sideways.

Instantly its grip on the Doctor weakened, allowing him to tear free.

He crawled away and turned, just in time to see Stoker fire the next shot.

The Dark rocked back, a jet of black ichor flying from its skull. The Dark shuddered and gagged, unable to comprehend what was happening.

'I'm glad you came to life,' said Stoker, advancing on the monster. 'It means you can die.'

The Dark grabbed Stoker and pulled her close, one giant hand grasped her head and twisting. But even as her neck snapped, Stoker squeezed the trigger on Cadwell's gun and the last round was discharged. The barrel of the gun was stuck deep into the Dark's throat. The back of its neck exploded, flinging black blood and gristle across the chamber.

For a long time the two figures remained together in a macabre hug.

Eventually Stoker's lifeless body slipped from the embrace and fell to the floor.

The Dark staggered backwards, choking on its own blood. A look of incredulous horror filled its gleaming black eyes.

'Is it dying?' Nyssa asked.

The Doctor stared impa.s.sively at the stumbling figure. 'I don't know.

But having taken on a physical form in our universe, the Dark is finally subject to the same physical rules as we are. It can can die. That, remember, is a condition of our existence.' die. That, remember, is a condition of our existence.'

A pool of thick, black blood had opened out beneath the struggling monster, oozing slowly down into the empty pit at the centre of the chamber.

The Dark wavered on the very edge of the pit. 'So... ' The voice was now a wet rasp of hate. 'Your own cheap trick, Doctor.'

The Doctor shook his head. 'Killing is no trick. It's all too easy.' The Dark spat out a brittle laugh. 'The irony... is not lost on me.'

'I don't rejoice in death. I don't believe in violence or cruelty. Where I can, I try to save life.'

The Dark swayed, and seemed to wither before them. Its midnight blood gushed from the wounds in its head and neck and spread across the floor. The voice had now fallen to a whisper. 'Then prove it.' S ave me!' ave me!'

The Doctor started forward, but Tegan held him back.

'Don't go near it!' He shrugged her hand away and stepped around the wide expanse of blood.

'I've already failed here.' the Doctor said, and pushed the Dark back into the open pit. It fell with a heavy crunch into the shadows.

Immediately, there was a sudden, thrashing ma.s.s of blackness that defied identification; something reared up from the mora.s.s, a head perhaps, with a pair of small, almost human eyes wide with agony and despair. Beneath the eyes was a sagging mouth full of jagged black fangs and membranous spittle.

The eyes fixed the Doctor with a terrible, imploring glare.

'Save me!' it screamed. it screamed.

'I can't,' the Doctor said.

Help me!'

The Doctor moved closer, clearly anguished. 'I can't,' he repeated. 'I can't.'

'Help me!' the dark ma.s.s screeched, spraying the air with blood and filth. the dark ma.s.s screeched, spraying the air with blood and filth.

Thin strands of blackness leapt from the pit, lashing at the Doctor with desperate ferocity. He fell back, watching the sinuous cords whip back and forth in an effort to locate him.

The strands groped at the air like the legs of a huge, dying spider; leaving a trail of blood wherever they touched. The blood boiled and sizzled and then ran back down into the pit.

Then, impossibly, the thing inside the pit began to pull itself back out, heaving its shrunken torso up on the spindly legs extruded across the chamber.

'It won't die!' Tegan yelled.

Several eyes snapped open inside the writhing ma.s.s and glared madly about the chamber.

'It's got to burn.' realised the Doctor suddenly. 'Of course!'

The Dark lashed out towards him and he dived over to where Stoker lay. She still hadn't moved. The Doctor quickly went through the pockets of her vest until he found the cigarette lighter.. It felt uncomfortably empty.

The Dark was out of the pit, trailing black slime. It started to crawl towards the Doctor like a giant, oil-soaked spider.

'Doctor!' cried Nyssa. She was throwing something to him. Bunny Cheung's bionic arm skidded to a halt by his feet.

The Doctor s.n.a.t.c.hed it up and tore at the synthetic skin until he had exposed the machinery beneath. Then he lit the cigarette lighter and jammed it underneath the arm's power cell. Something inside the arm must have been flammable because fire burst out immediately and singed the Doctor's hand.

He swung the burning limb awkwardly into the path of the Dark.

The flames disappeared into its oily gut as, squealing and spitting, the Dark raised itself for a final lunge.

Then the power cell in Bunny's arm exploded.

Bright fingers of flame rose up and grasped the Dark, igniting the film of black ooze that covered it. It shrieked and howled and threw itself backwards. The flames followed it into the pit. With a terrible cry, the thing rose shakily in one final grab for freedom. But the burning tendrils of blackness that formed its limbs could not support it and it sank, with a snapping crunch, back into the well. The fire took hold and it began to quiver uncontrollably, spitting and sizzling.

It took a full minute before the thing stopped moving altogether.

Eventually, even its nervous twitching ceased and the monster lay still in death. The flames ate noisily through its remains.

The Doctor turned away from the decrepit spectacle, his face grim.

He rested his hands on his companions' shoulders, as if offering rea.s.surance, but also taking comfort from their presence.

'Horrible,' said Tegan with a sob.

The Doctor moved to where Stoker had fallen. She lay with the unnatural slackness of death, her head at an ugly angle. But in the exposed flesh of her neck, a tiny pulse could be seen. The Doctor knelt down and touched her face. 'She's breathing.' he announced with some astonishment. 'It's faint, but she's alive...'

Tegan and Nyssa knelt down by Stoker as her eyelids fluttered open.

Her eyes were like little pools of melting honey. They gazed up at the Doctor but did not focus on him.

Her jaw worked as she tried to speak. 'Has... it... gone?'

'Yes.' the Doctor said.

Stoker's eyes closed softly. 'Then I can go now...' Then she smoothly, silently, relaxed into oblivion. The pulse in her throat slowly faded.

'Death after death.' the Doctor said quietly.

Epilogue.

The Doctor pulled the lever that controlled the TARDIS doors.

They whirred shut behind him and sealed out the rest of the universe. For a few seconds he simply stared at the control console, lost in thought.

'I can't believe we're back in the TARDIS,' said Tegan gratefully. 'Safe at last.'

'Is that true, Doctor?' Nyssa asked. 'Are we safe, now?'

The Doctor nodded. 'The Dark's consciousness died with its physical form. It can't reach us now.'

'How can you be sure?' Nyssa pressed. 'It was destroyed once before, remember.'

'Not like this.'

'What actually happened back there, Doctor?' Tegan wondered. 'I thought the Dark couldn't be stopped.'

'It couldn't. Not in its original form anyway - an immortal, evil intelligence left over from the remnants of the universe that existed before this one. It hung around the cosmos like a ghost searching for a way to exist properly. It nearly managed it on Akoshemon. But when it finally succeeded in taking on life, it sacrificed its immortality.'

'I thought you'd got it when you did that trick with the neurolectrin.'

'Ah, well. That was a pretty desperate ploy, I admit. But I'd seen Stoker, with Silas Cadwell's gun. She was waiting for her chance. In the end that's all I could do.'

'Did you realise... I mean, did you think that she would be killed as well?'

The Doctor glared at Tegan. 'How could I?'

Tegan glanced at Nyssa. Both felt a little troubled by the Doctor's solemn att.i.tude. It wasn't like him to be so taciturn.

'At the end when the Dark was dying in the pit, asking you to help it...'

'Begging me to help it, Tegan.'

'Whatever. Were you going to?'

The Doctor sighed and leant forward on the console. 'No.

It was merely trying to lure me closer. One last chance to kill me.'

'It would never have got the TARDIS if it had killed you,'

said Nyssa.

The Doctor began to operate the TARDIS controls. 'No, but it was motivated by the need for revenge, for destruction and death. That is all it had ever known, all it had ever believed in.'

'Then good riddance to it,' said Tegan. 'Why be so glum about it?'

'I was just thinking about all the people who died,' the Doctor said, as he flipped switches and twisted dials with great deliberation. And those that very nearly perished.'

'You mean us,' said Nyssa.

'We were the only ones to survive,' said Tegan heavily.

'None of us is indestructible' The Doctor looked grave. 'I thought I'd lost both of you at least once on this trip.'

Nyssa touched his arm. 'But we're still here'

'More by luck than design, I fear?

'Stop blaming yourself, Doctor,' Tegan said. 'You took the risks as as well as us. The important thing is that we survived, at least.' well as us. The important thing is that we survived, at least.'

'Yes, we should be thankful for that, I suppose.' The Doctor remained lost in thought, perhaps contemplating the moment when he had thought he had reached the end of the line, too, had been forced to look death in the face. He shivered. 'But there were many, many lives that were lost and destroyed because of the Dark.'

'You mean Vega Jaal, and Bunny and the others,' said Nyssa.