'You haven't won the game yet,' he declared.

He slowly began to circle the octogrammaton, forcing her round to maintain her opposition.

'I could always defeat you at chess, Merlin,' she warned.

He stopped, for Morgaine now had her back to the open portal of the vortex. Behind him, he heard the Destroyer laughing to itself. 'Who said anything about playing chess?' said the Doctor. 'I'm playing poker!'

Ace hurtled out of the vortex with a whoosh and collided with the Queen. The sword flew from her grasp, spinning through the air until its hilt dropped homeward into its maker's open hand. 'And I had an Ace up my sleeve,' he cried, brandishing Excalibur.

The vortex slammed shut.

'Very funny,' complained Ace as she scrambled to her feet.

Morgaine turned in rage to the demon. 'Destroy him!'

she yelled.

The creature stepped forward and raised its chained arms. Release me.'

Its demand was too eager. Morgaine's actions faltered.

'Which is it to be, Morgaine?' goaded the Doctor. 'Who do you fear more?'

'This is no threat, Merlin,' she cried. 'Return Excalibur or I shall unleash the Destroyer upon this world.'

'Stuff and nonsense,' snapped the Doctor.

Morgaine's eyes blazed. She turned upon the demon and flung wide her arms in a gesture of release.

The links of wrought silver fell apart and the manacles splintered. With a smile that grew from a snarl to a roar, the Destroyer raised its hands in triumph.

Its shape altered and grew. The tailored suit split as great thorns spiked out across its body like the armour of all h.e.l.l's legions.

Its head lost all human features; its skin hardened into scales of metallic blue; its goat horns twisted and blackened in thick murderous spires. As it rose up, its eyes narrowed and darkened into green pits of burning evil.

Ace clung to the Doctor. 'Nice work,' she said.

He stared up at the towering abomination. 'I thought she was bluffing,' he said lamely.

The Brigadier lay in the long gra.s.s outside the priory wall where he had been thrown. His head was awash with disparate thoughts and memories... or were they just his fancy?

Doris was patting down the soil around the apple tree.

On Radio 4, the newsreader was saying: 'The General Secretary of the United Nations Intelligence Taskforce, Mrs Eva Carlshorst, has again denied reports of Taskforce, Mrs Eva Carlshorst, has again denied reports of casualties amongst UNIT personnel operating in the south-west casualties amongst UNIT personnel operating in the south-west of England...' of England...'

Doris was reaching for the portable phone.

'I want to speak to Brigadier Alastair Lethbridge-Stewart.' Her hair caught the sunlight through the french windows and glistened. 'Well, where is he?'

A gloved hand seized the Brigadier's collar and yanked him up into reality.

Mordred's face was barely inches from his own.

'Where is she?' he demanded.

The Brigadier swallowed wearily. 'To whom are you referring?'

The Prince swore and pushed him back to the ground, before stalking angrily towards the priory door.

'Free!' roared the Destroyer. 'Free!'

The demon slavered as its brutal frame grew still more immense; its arms raised, already pressing against the skeletal beams of the roof. It gave off a stench of putrefaction.

'You fool, Morgaine,' accused the Doctor. 'Do you think this'll solve anything?'

He stepped back in awe of the monster, and before he knew it, Morgaine had again s.n.a.t.c.hed Excalibur from his hands.

Holding the weapon against her enemy, she backed within the bounds of the octogrammaton. 'Too late, Merlin. The gateway is open. I am gone and you are lost!'

She turned to leave, but the door of the hall was flung wide open. On the threshold stood Prince Mordred, his sword in hand.

'Mother!' he said.

'Mordred.' Again she faltered, confronted by the child she had herself sacrificed.

'And about time,' complained the Doctor.

'You live,' said Morgaine, her voice trembling.

He advanced into the hall, ignoring the monster that loomed above them all. 'No thanks to you, false parent!

Witch!'

'Mordred, I thought you were dead.'

'Thought or wished it so?'

He stepped into the octogrammaton with her and she raised a hand to stroke his hair. 'Mordred, no. That was not the way of it.'

As they started to fade, the Doctor swung out with his umbrella handle and hooked Excalibur away from Morgaine. She turned with a glare of helpless rage. Then she and her son were gone.

Morgaine's legacy loomed over the Doctor and Ace. The Destroyer, waiting, taking great draughts of air, as a dragonfly rests after its emergence, before launching on its first flight.

The Doctor was staring up at the monstrosity, intoxicated by its manifestation of raw evil. Of the 7,405,926 demons on the Talmudic table, this fiend probably made it into what Ace would call the Top Ten.

Ace tugged at his sleeve. 'Doctor, can I have a word...' She hardly dared move for fear of attracting the demon's attention.

The Doctor took her arm and they edged for the door.

'Merlin...' The Destroyer's voice came deeply and slowly.

The door opened and Lethbridge-Stewart barred the way. His eyes widened as he took in the towering presence of the Destroyer. He met its cold glare and knew he was a marked man.

'Brigadier, you're going the wrong way!' The Doctor grabbed his shoulder and tried to force him back. Behind them, the monster began to stir.

Ace fumbled in her pockets and panicked. She looked back and saw her case of bullets lying on the hall floor, near the Destroyer's taloned hooves.

She ran back.

'Ace!' yelled the Doctor.

As she grabbed up the case, the monster's hoof kicked out wildly and took her on the hip. She went tumbling across the hall, only to be caught somehow in the Doctor's arms.

He hurried her out, followed by the Brigadier. As they ran into the evening air, they heard the Destroyer's cry of rage and hunger.

The Doctor found a path that led away from the building. Once they were clear of the priory grounds, he set Ace down. She was only winded and sat quietly recovering her breath.

There was a steady distant rumble like growing thunder. The sh.e.l.l of the priory was beginning to flicker with green light.

'What was that?' said the Brigadier.

The reply was almost casual. 'That, Brigadier, was the end of the world.'

The old soldier nodded. 'Same as ever, eh Doctor?' But he had not forgotten the predatory eyes or how they had d.a.m.ned his soul.

The Doctor stamped at the ground with his brolly. 'Oh, this is no good at all!'

'I can have an airstrike in minutes,' suggested the Brigadier.

'No. Conventional weapons won't even scratch it.'

'How about silver bullets?' said Ace.

'Silver would do the trick, getting some is another matter.'

'Professor.' She held up the bullet-case for him.

The Brigadier finally appreciated the care with which the Doctor selected his relentlessly unorthodox companions. 'Splendid,' he said.

The Doctor beamed at the contents of the case.

'Excellent work, Ace. Brigadier, give me your gun.'

He opened the pistol and started to load the silver rounds into the chamber.

'You er... just fire the bullets into the monster, do you?'

enquired the Brigadier.

'Yes, yes, it's that simple, like most killings.' The Doctor snapped the gun shut.

'Good Lord,' said the Brigadier, staring over the Doctor's shoulder. 'Look at that s.p.a.ceship.'

'What?' As the Doctor turned to look, he was caught square on the jaw by Lethbridge-Stewart's fist.

He went down senseless.

'You toerag!' Ace stared in blind rage as the Brigadier picked up the pistol.

'Sorry Doctor, but I think I'm more expendable than you are.' He ran back down the path towards the burning priory, leaving Ace alone, furiously trying to rouse her mentor.

Along the path he ran, his feet pounding and his breath short. But he had to face those cruel eyes again.

Doris was on the phone and getting angrier.

'Yes, I am Mrs Lethbridge-Stewart... A message? Oh, I don't know. Tell him I lo... Tell him he hasn't finished the garden.'

Their apple tree, full grown, heavy with russet fruit; then a great wind tore at it, ripping its roots until it crashed in ruin across her lawn.

Alastair Gordon Lethbridge-Stewart reached the door of the priory. The ground trembled. Smoke was curling acridly into his lungs as he pushed his way inside.

Timbers and rafters blazed around the Destroyer like a throne of green fire. It was hunger. This world was its to devour, and then another and another. All life would not a.s.suage the terrible famine that raged inside its heart. Its raised hands belched energy, out through the burning roof into the sky.

It exalted in its freedom and roared its agony. Hunger would prevail. 'And today I shall feed!'

Beside its hooves, it noticed the figure of a human. With a convulsive movement, it drew its power back into itself and fixed him with its eyes. It knew him.

'Little man, what do you want?'

The Brigadier levelled his pistol at the demon. 'Get off my world,' he said.

The Destroyer bared its fangs. 'Pitiful. Can this world do no better than you as a champion?'