'It's not a woman! It's . . . it's a film creature, you idiot! Do you think I'm really that big?' shouted Ginger. 'It's using Holy Wood! It's a Holy Wood monster! From film land!'

'Steer, godsdamnit! Steer!'

'I don't know how to!'

'You just have to throw your weight about!'

The Bursar gripped the broomstick nervously. It's all very well for you to say, he thought. You're used 'to it.

They had been stepping out of the Great Hall when a giant woman had lurched past the gate with a gibbering ape in one hand. Now the Bursar was trying to control an antique broom out of the University museum while a madman behind him feverishly tried to load a crossbow.

Airborne, the Archchancellor had said. It was absolutely essential that they were airborne.

'Can't you keep it steady?' the Archchancellor demanded.

'It's not made for two, Archchancellor!'

'Can't damn well aim with you weavin' around the sky like this, man!'

The contagious spirit of Holy Wood, whipping across the city like a steel hawser with one end suddenly cut free, sliced once again through the Archchancellor's mind.

'We don't leave our people in there,' he muttered.

'Apes, Archchancellor,' said the Bursar automatically.

The Thing lurched towards Victor. It moved uneasily, fighting against the forces of reality that tugged at it. It flickered as it tried to maintain the shape it had climbed into the world with, so that images of Ginger alternated with glimpses of something that writhed and coiled.

It needed magic.

It eyed Victor and the sword, and if it was capable of something so sophisticated as knowledge, it knew that it was vulnerable.

It turned, ant bore down on Ginger and the wizards.

Who burst into flame.

The Dean burned with a particularly pretty blue colour.

'Don't worry, young lady,' said the Chair from the heart of his fire. 'It's illusion. It's not real.'

'You're telling me?' said Ginger. 'Get on with it!'

The wizards moved forward.

Ginger heard footsteps behind her. It was the Dibblers.

'Why's it frightened of the flame?' said Soll, and the Thing backed away from the advancing wizards. 'It's just illusion. It must be able to feel there's no heat.'

Ginger shook her head. She looked like someone surfing on a curling wave of hysteria, perhaps because it is not every day you see giant images of yourself trampling down a city.

'It's used Holy Wood magic,' she said. 'So it can't disobey Holy Wood rules. It can't feel, it can't hear. It can only see. What it sees is what is real. And what film fears is fire.'

Now the giant Ginger was pressed against the tower.

'Well, it's trapped,' said Dibbler. 'They've got it now.'

The Thing blinked at the advancing flames.

It turned. It reached up with its free hand. It began to climb the tower.

Victor slid off his horse and stopped concentrating. It vanished.

Despite his panic, he found room for a tiny gloat. If only wizards had gone to the clicks, they'd have known exactly how to do it.

It was the critical fusion frequency. Even reality had one. If you could only make something exist for a tiny part of a second, that didn't mean you'd failed. It meant you had to keep on doing it.

He scurried crabwise along the base of the tower, staring up at the climbing Thing, and tripped over something metallic. It turned out to be the Librarian's dropped pike. A little further off, the end of the rope trailed in a puddle.

He stared at them for a moment, then used the pike to chop a few feet off the rope to make a crude shoulder strap for the weapon.

He grabbed the rope and gave it an experimental tug, and then . . .

There was an unpleasant lack of resistance to the pull. He threw himself backwards just before hundreds of feet of sodden rope smacked damply on to the paving.

He looked around desperately for another route to the top.

The Dibblers watched open mouthed as the Thing climbed. It wasn't moving very fast, and occasionally had to wedge the gibbering Librarian into a handy buttress while it found the next handhold, but it was moving up.

'Oh, yes. Yes. Yes,' breathed Soll. 'What a picture! Pure kinema!'

'A giant woman carrying a screaming ape up a tall building,' sighed Dibbler. 'And we're not even having to pay wages!'

'Yeah,' said Soll.

'Yeah . . . ' said Dibbler. There was a tiny note of uncertainty in his voice.

Soll looked wistful.

'Yeah,' he repeated. 'Er.'

'I know what you mean,' said Dibbler slowly.

'It's . . . I mean, it's really great, but . . . well, I can't help feeling . . . '

'Yeah. There's something wrong,' said Dibbler flatly.

'Not wrong,' said Soll desperately. 'Not exactly wrong. Not wrong as such. Just missing . . . ' He stopped, at a loss for words.

He sighed. And Dibbler sighed.

Overhead, the thunder rolled.

And out of the sky came a broomstick with two screaming wizards on it.

Victor pushed open the door at the base of the Tower of Art.

It was dark inside, and he could hear water dripping down from the distant roof.

The tower was said to be the oldest building in the world. It certainly felt like it. It wasn't used for anything now, and the internal floors had long ago rotted away, so that all that was left inside was the staircase.

It was a spiral, made of huge slabs set into the wall itself. Some of them were missing. It'd be a dangerous climb, even in daylight.

In the dark . . . not a chance.

The door slammed open behind him and Ginger strode in, dragging the handleman behind her.

'Well?' she said. 'Hurry up. You've got to save that poor monkey.'

'Ape,' said Victor absently.

'Whatever.'

'It's too dark,' Victor muttered.

'It's never too dark in the clicks,' said Ginger flatly. 'Think about it.'

She nudged the handleman, who said, very quickly, 'She's right. 'S never dark in the clicks. Stands to reason. You've got to have enough light to see the dark by.'

Victor glanced up at the gloom, and then back at Ginger.

'Listen!' he said urgently. 'If I . . . if something goes wrong, tell the wizards about the . . . you know. The pit. The Things will be trying to break through there, too.'

'I'm not going back there!'

There was a roll of thunder.

'Get going!' shouted Ginger, white-faced. 'Lights! Picture box! Action! And stuff like that!'

Victor gritted his teeth and ran for it. There was enough light to give the darkness a shape, and he leapt from stair to stair with the magic of Holy Wood reciting its litany in his head.

'There has to be enough light', he panted, 'to see the darkness.'

He staggered onwards.

'And in Holy Wood I never run out of strength,' he added, hoping his legs would believe him.

That took care of the next turn.

'And in Holy Wood I have to be in the nick of time,' he shouted. He leaned against the wall for a moment and fought for breath.

'Always in the nick of time,' he muttered.

He started to run upwards again.

The slabs passed under his feet like a dream, like squares of movie clicking through the picture box.

And he'd arrive in the nick of time. Thousands of people knew he would.

If heroes didn't arrive in the nick of time, where was the sense in anything? And-

There was no slab in front of his falling foot.

His other foot was already arching to leave the step.

He focused every ounce of energy into one tendontwanging push, felt his toes hit the edge of the next slab up, flung himself forward and then jumped again because it was that or snap a leg.

'This is nuts.'

He ran onward, straining to look for more missing slabs.

'Always in the nick of time,' he muttered.

So maybe he could stop and have a rest? He could

still make it in the nick of time. That's what the nick of time meant . . .

No. You had to play fair.

There was another missing slab ahead.

He stared blankly at the space.

There was going to be a whole tower of this.

He concentrated briefly and jumped on to nothing. The nothing became a slab for the fraction of a second he needed to jump off on to the next one.

He grinned in the dark, and a sparkle of light twinkled on a tooth.

Nothing created by Holy Wood magic was real for long.

But you could make it real for long enough.

Hooray for Holy Wood.

The Thing was flickering more slowly now, spending less time looking like a giant version of Ginger and more looking like the contents of a taxidermist's sink trap. It pulled its dripping bulk over the top of the tower and lay there. Air whistled through its breathing tubes. Under its tentacles the rock crumbled, as the magic drained away and was replaced by the hungry appetite of Time.

It was bewildered. Where were the others? It was alone and besieged in a strange place . . .

. . . and now it was angry. It extended an eye and glared at the ape struggling in what had been a hand. Thunder rocked the tower. Rain cascaded off the stones.

The Thing extended a pseudopod and wrapped it around the Librarian's waist . . .

. . . and became aware of another figure, ridiculously small, erupting from the stairwell.

Victor unslung the pike from his back. What did you do now? When you were dealing with humans you had options. You could say 'Hey, put down that ape and come on out with your feelers up.' You could . . .

A claw-tipped tentacle as thick as his arm slammed down on the stones, cracking them.

He leapt backwards and brought the pike around in a backhanded swipe that drew a deep yellow slash in the Thing's hide. It howled and shuffled around with unpleasant speed to flail more tentacles at him.

Shape, thought Victor. They've got no real shape in this world. It has to spend too much time holding itself together. The more it has to concentrate on me, the less it can concentrate on not falling to bits.

An assortment of mismatched eyes extended from various bits of the Thing.

As they focused on Victor they crinkled with angry bloodshot veins.

OK, he thought. I've got its attention. Now what?

He stabbed at a snapping claw and jumped with his knees up under his chin when a mercifully unidentifiable pseudopod tried to chop his legs from under him.

Another tentacle snaked out.

An arrow passed through it with the same effect as a steel pellet shooting through a sock filled with custard. The Thing screeched.

The broomstick barrelled over the top of the tower, with the Archchancellor feverishly reloading.

Victor heard a distant, 'If it bleeds, we can kill it!' followed by 'What do you mean, we?'

Victor pressed forward, hacking at anything that looked vulnerable. The creature changed form, trying to thicken its hide or grow a carapace wherever the pike fell, but it wasn't fast enough. They're right. It can be killed, Victor thought. It may take all day, but it's not invincible -. . .

And then there was Ginger in front of him, her expression filled with pain and shock.

He hesitated.

An arrow thudded into what might have been its body.

'Tally ho! Take us round again, Bursar!'

The image dissolved. The Thing screeched, threw the Librarian aside like a doll, and lurched at Victor with all tentacles at full stretch. One of them knocked him over, three others dragged the pike from his hands, and then the Thing was rearing up, like a leech, raising the iron pike to knock its tormentors out of the sky.

Victor raised himself up on his elbows and concentrated.

Just real for long enough.

The lightning bolt outlined the Thing in blue-and-white light. After the thunderclap the creature swayed drunkenly, with little tendrils of electricity coruscating across it and making whizzing noises. A few limbs were smoking.