The Doctor smiled, thought for a moment, then walked over to the moist grey bulk of Azathoth.

'Can you hear me?' he cried.

Azathoth remained stubbornly silent. The Doctor waved a hand at Ace.

'You can answer,' she said. 'The missile won't explode. Yet. But if I hear anything that sounds like it might change my mind in a way I won't like, I'll make sure that your mind changes into a pile of mush on the walls.'

'I hear you,' Azathoth replied sulkily. 'Blasph . . . '

'Yes, yes, we'll take that as read, thank you very much,' the Doctor said.

'Azathoth, I offer you a choice.'

'There is no choice. I am G.o.d. I do what I wish.'

'You are no G.o.d, and you know it. You're just a fake deity whose powers are limited to a rather forceful form of persuasion.'

There was a thud as the caravan settled to the ground. I could hear the hiss of ropes sliding down the outside as the raksha.s.si released them.

'What is your offer?'

'Stop this invasion. Stay here on Ry'leh.'

'And what do you give me in return?'

'Your life.'

Azathoth laughed: great quaking peals of laughter that caused its body to quake and the wooden floor beneath it to creak alarmingly.

'What power do you puny creatures have over the life of mighty Azathoth?'

'Have you forgotten the missile that guards you?'

'If you mean the most recent convert to the cult of Azathoth, no. We have been enjoying a long conversation: The Doctor's face fell, and he began to back away. 'Missile,' Azathoth continued, 'kill the Doctor.'

Chapter 18.

In which one disaster is sought and another one narrowly avoided.

The tiny black object that had been hovering in front of Azathoth's s...o...b..ring maw suddenly darted away.

The Doctor turned to run. Circling quickly, the missile sped for the Doctor's back in a blur of ebony. The Doctor tripped over his own feet and went sprawling, leaving the missile to overshoot its target.

'Disengage!' Ace yelled. 'Do you hear me, disengage!'

Azathoth was giggling.

I dropped to the floor and whipped out my trusty revolver. The missile was heading straight for the Doctor's face, but I managed to deflect its path with a well-placed bullet. For a moment I thought that I had crippled it, but it recovered its momentum quickly and headed straight for the Doctor again.

He had climbed to his feet and was pressed against the wall with nowhere else to run. The missiles sped directly for his wide-eyed face. I fired again, but missed.

The Doctor threw himself to the floor. The missile hit the wall and exploded, sending a hail of wooden splinters across the caravan. Several of them hit Azathoth, who howled in pain. Through the hole I could make out the rocky surface of Ry'leh.

'Quickly,' I shouted, 'before anybody investigates.'

I stood by the hole and helped the others as they scrambled through. The Doctor was last, and caught his coat upon a projecting spar of wood.

'With friends like Ace. . .' he muttered as I disentangled him.

Within seconds I was outside with the rest of them. As we ran off, Azathoth's plaintive voice tugged at my mind.

'Listen to me. . .' it shouted, its voice growing fainter and fainter. 'I can offer you peace and happiness and a place in heaven.. .'

I was not the only one to stop and look back, but we kept on going none the less.

We took refuge finally in a small clump of bushes. They snapped at us tentatively, but the size and mood of our party obviously frightened them and they returned to sleep with their buds safely tucked beneath their leaves.

'Look,' said Bernice, gazing upwards in wonder. Her face seemed to shine.

At first I thought that it was her inner beauty, but then I followed her gaze.

For the first time in a thousand years the sun was shining upon the surface of Ry'leh. Its rays were pouring through the hole in the sky, surrounded by concentric rings of cloud, and shone down like a stage spotlight upon the plain where the caravans were landing. Raksha.s.si hovered high above, looking for us, the shadows of their wings skimming across the ground like lithe black animals.

'There is a crack in everything,' the Doctor whispered. 'That's how the light gets in.'

'Pardon?' I said.

'A line of poetry from my home planet. I think it loses something in translation.'

In the distance, illuminated by the finger of light, the fakirs were emerging from the landed caravans. They immediately formed up into lines and began to chant.

'I-ay, I-ay!' The words echoed across the plain. 'Naghaa, naghaighai!

Shoggog fathaghn! I-ay, I-ay tsa toggua tholoya! Tholoya fathaghn! I-ay Azathoth!'

The words repeated, growing louder as more voices joined the chorus, throbbing like a heartbeat in the distance. I felt, as I did the last time that I heard those words, that a pressure was building up behind my eyes.

'They don't waste much time, do they?' Bernice said.

'It's their big moment,' Ace replied. 'And besides, the Shlangii will soon be here.'

'How soon?' the Doctor asked.

'The nearest garrison is a small one, so let's a.s.sume that it's been wiped out during the battle with Maupertuis's men. The next one is half-way around the planet, but they've got skimmers. Giving them an hour to work out that something has happened, and another fifteen minutes to mobilize .

. . I guess half an hour until they arrive.'

'Too long. Azathoth will be through to India by then.'

'So what are our options?' Holmes asked.

'I don't know,' the Doctor said.

Bernice gazed sceptically at him.

'No cards up the sleeve?'

'None.'

'No long-range plans?'

'Not one.'

'Scout's honour?'

'May my woggle fall off if I lie.'

'That chant,' Ace said thoughtfully. 'You said it weakens the fabric of reality, whatever that is, enabling a gateway to be opened, and you also said that this fabric thing is already weakest between India and this plain.'

'Indeed.'

'Well, how easy would it be to move the gateway? What I mean is, could we change the chant and alter the aim point?'

The Doctor thought for a moment.'

'Hmm. A canny notion, and one well worth bearing in mind. What made you think of it?'

Ace smiled. 'Something I overheard while I was hanging around waiting for you to arrive,' she said.

Delving around in his pockets, the Doctor finally pulled out a piece of green chalk. 'No paper,' he complained. He looked around for something to write on, and his eyes lit up as their penetrating gaze crossed Ace's battle-armour.

'Ace, turn around.'

'You what?'

'Just do it!'

He began to scribble on the matt-black surface, quickly covering it with symbols and small diagrams, some of which I recognized from the inscriptions on Azathoth's caravan. Sometimes he would go back and rub a line out with his sleeve: once or twice he retrieved chalks of other colours and added notes in and around his original ones. Holmes was following the Doctor's calculations so closely that he ended up with chalk-dust on the tip of his nose. The Doctor kept up a running barrage of commentary, muttering phrases such as: 'Of course, the rhomeson flux must be taken into account. . : , 'it's important to remember that E equals MC cubed in the exo-s.p.a.ce time continuum. . : and 'for heaven's sake, keep still Ace!'

The chant was building up, with individual voices soaring above the main theme, and a strong beat pushing it along. My head was beginning to throb in sympathy.

Finally the Doctor leaned back and sighed.

'This would have been so much easier with the books from the Library, but Sherringford still has them. Fortunately I had a quick flick through some of them, and I also managed to chat with one or two of the fakirs when we were on our way to the surface. I think we can do it.'

'How?' said Ace, stretching after sitting in a cramped position for so long.

'The whole thing is frequency-specific. It's the subtle shifting of discords that weakens the structure of s.p.a.cetime, enabling the connection to be made with the nearest world - Earth. If we introduce a specific set of new discords, we can move the point of connection.'

'But why didn't Azathoth or Sherringford think of that?' I asked.

'Because they were thinking in purely spatial terms,' the Doctor replied.

'And the frequencies required are just too high to achieve. It never occurred to them to move the aim-point in time. The calculations are harder, but the frequencies can be sung, and the further forward or back in time we move the aim point, the wider our spatial error can be.'

'In time,' Holmes breathed. 'You mean . . .?'

'I mean I'm looking for suggestions as to the best place to dump an evil G.o.d and its worshippers. Somewhere that they can't do any major harm. A geological disaster would do perfectly. Eighteen eighty seven, plus or minus fifty years, and on the Earth's surface. That's our window of opportunity. Once we dump them, we can sing our own way back to Tir Ram's cavern, and from there we can make our way home.'

Bernice thought for a moment, then said, 'What about Siberia, nineteen-oh-eight? The TARDIS explosion?'

'No,' the Doctor snapped. 'If I start mixing dimensional rips they could end up anywhere.'

'Krakatoa!' I exclaimed. 'Four years ago. If it's an explosion you're looking for, that's the biggest one I can remember.'

'Is that east or west of Java?' the Doctor said, then thought for a moment.

'A distinct possibility,' he added, 'but a trifle dangerous if we get caught up in it. Ditto the t.i.tanic in nineteen twelve, which I was also considering, with the added problem that we would be interfering in our own pasts. Has it occurred to you that we seem to have toured most of the major disasters of the late-nineteenth and early-twentieth centuries in the past few months?'

'California,' said Ace quietly. 'Nineteen-oh-six. The great San Francisco earthquake.'

'Perfect!' the Doctor shouted. 'We missed that one. What made you think of that?'

'Personal interest,' she replied. 'It was an old school History project.'

History?, I thought, then let it slip away.

The Doctor delved in his pockets and pulled out a large, leather-bound book.

'My five-hundred-year diary,' he said, catching my inquiring glance. 'All sorts of information that's completely pointless unless you are trying to avert an alien invasion.'

He flicked through the pages.

'Now let me see . . . We'll need a location which is known to have been completely wiped out. We can't risk them escaping. That rules out quite a bit of the town...'

His scowl deepened as his fingers riffled through page after page.

'Town Hall . . . no. Agnews State Insane Asylum . . . no. Palace Hotel...'

A smile broke across his face.

'Yes! Razed to the ground.'